# BloodSight

> Reference library for blood test results: 194 biomarkers across 18 lab panels, 62 side-by-side comparisons, and 34 interpretation guides. BloodSight also organizes a person's own lab reports and tracks values over time.

BloodSight is an informational and personal health organization tool. It is not a substitute for professional medical advice, diagnosis, or treatment, and it does not provide clinical recommendations.

## Product

- [3 Best Ways to Analyze Blood Test Results: AI vs Apps (2026)](https://bloodsight.com/best-blood-test-analyzer-apps): Compare 3 ways to analyze blood test results in 2026: ChatGPT and Claude, longevity memberships, and dedicated lab analyzers. Accuracy, privacy, price.
- [Blood Test Results App in Plain Language](https://bloodsight.com/blood-test-results-app): A web app for blood test results: upload a PDF or photo and get the whole report explained, value by value, with each lab's own range beside it.
- [Blood Test Tracker: One Timeline for Every Lab](https://bloodsight.com/blood-test-tracker): A blood test tracker for every lab: upload PDFs or photos from Quest, Labcorp, MyChart or a hospital and follow each biomarker on one timeline.
- [Function Health Alternative for Lab Results](https://bloodsight.com/function-health-alternative): Compare Function Health and BloodSight for lab analysis, tracking, price, clinician review, outside lab uploads, family records. Updated September 2026.
- [InsideTracker Alternative for Lab Analysis](https://bloodsight.com/insidetracker-alternative): Compare InsideTracker and BloodSight on uploaded blood results, supported biomarkers, recommendations, tracking, family profiles, price, and turnaround.
- [Sample Blood Test Analysis: AI Report Example](https://bloodsight.com/sample-blood-test-analysis): See a fictional blood test analysis end to end: source report, extracted values, plain-language explanations, marker patterns, and a multi-year trend.
- [SelfDecode Alternative for Lab Results Analysis](https://bloodsight.com/selfdecode-alternative): Compare SelfDecode Labs Analyzer and BloodSight on price, optimal ranges, lab report uploads, recommendations, DNA, tracking, and family profiles.
- [Labcorp Results Tracker & Analyzer](https://bloodsight.com/track-labcorp-results): Upload a Labcorp PDF and BloodSight reads every value, explains it in plain language, and charts your history across visits from Labcorp, Quest or any lab.
- [Track MyChart Lab Results Across Providers](https://bloodsight.com/track-mychart-lab-results): Download MyChart lab results as a PDF, get the report explained, and track values across multiple MyChart organizations, Quest, Labcorp, and other labs.
- [Track & Analyze Quest Diagnostics Results](https://bloodsight.com/track-quest-results): Learn how to save Quest Diagnostics results, upload the report for AI analysis, and track Quest values alongside Labcorp, MyChart, and other labs.

## Lab panels

- [Blood test panels](https://bloodsight.com/panels): Index of every lab panel covered.
- [Iron Studies](https://bloodsight.com/panels/iron-studies): How to read iron studies as one picture: what ferritin, serum iron, TIBC, and transferrin saturation mean together — deficiency, inflammation, or overload.
- [Tumor Markers](https://bloodsight.com/panels/tumor-markers): Tumor markers are monitoring tools, not cancer screens. Why an elevated PSA, CEA or CA-125 is usually benign, and a normal one can still miss cancer.
- [Autoimmune Panel](https://bloodsight.com/panels/autoimmune-panel): A positive ANA on an autoimmune panel is a question, not a verdict. How the specific antibodies name the disease, and why complement falls as lupus flares.
- [Vitamins and Nutrients](https://bloodsight.com/panels/vitamins-and-nutrients): How to read vitamin and nutrient blood tests: the D, B12, and folate trio, gray zones where 'normal' still causes symptoms, and the testing traps to avoid.
- [Bone Health Panel](https://bloodsight.com/panels/bone-panel): These markers don't measure how much bone you have, they track how fast it's changing, and can flag treatment working before a bone scan can.
- [Heavy Metals Panel](https://bloodsight.com/panels/heavy-metals-panel): A heavy metals panel has no optimal level to aim for, and a normal blood result mostly rules out recent exposure, not a stored body burden.
- [Allergy Panel](https://bloodsight.com/panels/allergy-panel): The allergy blood test can't tell you what you're allergic to. Total IgE measures only allergic tendency; tryptase is a timed mast-cell marker.
- [Cardiac Markers](https://bloodsight.com/panels/cardiac-panel): The cardiac panel is two panels: acute markers read against an ER clock where timing decides everything, and slow markers of strain and long-term risk.
- [Coagulation Panel](https://bloodsight.com/panels/coagulation-panel): A coagulation panel asks two opposite questions: why blood won't clot enough and why it clots too much. How PT, aPTT and D-dimer read together.
- [Thyroid Panel](https://bloodsight.com/panels/thyroid-panel): How to read a thyroid panel as one picture: the TSH–T4 pattern grid, what antibodies add, the biotin trap, and what borderline results usually mean.
- [Diabetes Panel](https://bloodsight.com/panels/diabetes-panel): A diabetes panel reads the same blood sugar across three time windows, plus the insulin numbers behind it. Why the A1c average can read falsely in anemia.
- [Hormone Panel](https://bloodsight.com/panels/hormone-panel): A hormone panel is several endocrine axes sharing one name. Why each value is read beside its partner and against the clock, almost never alone.
- [Complete Blood Count (CBC)](https://bloodsight.com/panels/complete-blood-count): The CBC is three reports printed as one: red cells, white cells, platelets. See how MCV and RDW classify an anemia hemoglobin alone can't.
- [Inflammation Markers](https://bloodsight.com/panels/inflammation-panel): Inflammation markers all rise together but aren't interchangeable: they differ by speed, trigger, and location, and CRP and hs-CRP are one molecule.
- [Kidney Function Panel](https://bloodsight.com/panels/kidney-panel): The basic kidney numbers signal late and muscle fools them. How urine albumin, cystatin C and the BUN-creatinine ratio catch kidney trouble earlier.
- [Lipid Panel](https://bloodsight.com/panels/lipid-panel): On most lipid panels LDL is calculated, not measured, and it weighs cholesterol rather than counting particles. How non-HDL, apoB and Lp(a) read the gap.
- [Liver Function Panel](https://bloodsight.com/panels/liver-panel): Liver function tests mostly measure damage and blocked bile flow, not function. How ALT, AST, ALP and GGT read as a pattern, and where the real work shows.
- [Comprehensive Metabolic Panel (CMP)](https://bloodsight.com/panels/metabolic-panel): The CMP is the checkup test you didn't order. Why one flagged value rarely means much, and how the electrolyte, kidney and protein clusters read together.

## Biomarkers

- [Biomarker directory (A–Z)](https://bloodsight.com/biomarkers): Alphabetical index of every biomarker page.

### Iron Studies

- [Ferritin](https://bloodsight.com/biomarkers/ferritin): Ferritin shows how much iron your body has stored. Ranges for men and women, why low stores are tied to fatigue and hair loss, and what a high level means.
- [Total Iron-Binding Capacity (TIBC)](https://bloodsight.com/biomarkers/tibc): TIBC measures how much iron your blood can carry. A high result usually signals low iron, not too much. Ranges, low vs high meaning, the transferrin link.
- [Iron (Fe)](https://bloodsight.com/biomarkers/iron): Serum iron looks like the main iron test but swings 20–30% in a day with meals and supplements. What low and high mean, and why doctors read it in context.
- [Transferrin](https://bloodsight.com/biomarkers/transferrin): Transferrin is the iron-carrier protein your lab often reports as TIBC instead. Ranges, why it falls with inflammation, and how to read it with iron.
- [Iron Saturation (TSAT)](https://bloodsight.com/biomarkers/iron-saturation): TSAT is the only ratio on the iron panel: the percent of transferrin's seats filled. Why a low or high TSAT settles what ferritin alone can't.
- [Soluble Transferrin Receptor (sTfR)](https://bloodsight.com/biomarkers/soluble-transferrin-receptor): Why soluble transferrin receptor (sTfR) stays honest when inflammation props up ferritin, how it separates iron deficiency from anemia of chronic disease.

### Tumor Markers

- [Cancer Antigen 125 (CA-125)](https://bloodsight.com/biomarkers/ca-125): A CA-125 over 35 U/mL frightens people, but periods, pregnancy, endometriosis and fibroids raise it too. What the number means and why it can't screen.
- [Alpha-Fetoprotein (AFP)](https://bloodsight.com/biomarkers/afp): A high alpha-fetoprotein (AFP) often means a regenerating liver, not cancer. How to read the 0-40, 40-200, and >200 ng/mL bands in context.
- [Cancer Antigen 19-9 (CA 19-9)](https://bloodsight.com/biomarkers/ca-19-9): CA 19-9 is a tumor marker for pancreatic cancer, but about 1 in 15 people cannot make it, so a normal result proves nothing for them. What it means.
- [Beta-hCG (β-hCG)](https://bloodsight.com/biomarkers/beta-hcg): Why one beta-hCG number means little in early pregnancy, how the ~48-72h doubling trend is read, what slow and fast rises mean, plus hCG as a tumor marker.
- [Cancer Antigen 15-3 (CA 15-3)](https://bloodsight.com/biomarkers/ca-15-3): CA 15-3 is a breast cancer monitoring marker, not a screening test. A single value confirms little; the trend across draws carries the signal.
- [Neuron-Specific Enolase (NSE)](https://bloodsight.com/biomarkers/nse): A high NSE often points at the sample, not the patient. Why hemolysis fakes elevated neuron-specific enolase, and how to read the number honestly.
- [Cancer Antigen 27-29 (CA 27-29)](https://bloodsight.com/biomarkers/ca-27-29): CA 27-29 is a breast cancer monitoring marker. Why one value above 38 says little, and why the direction across repeated draws is what doctors act on.
- [Chromogranin A (CgA)](https://bloodsight.com/biomarkers/chromogranin-a): A high chromogranin A scares people toward a tumor diagnosis, but a common heartburn pill is one of the top reasons it climbs with no tumor at all.
- [Prostate-Specific Antigen (PSA)](https://bloodsight.com/biomarkers/psa): PSA is prostate-specific, not cancer-specific. What a high PSA means, why a 4.0 cutoff leaks both ways, free PSA, and the screening debate.
- [Carcinoembryonic Antigen (CEA)](https://bloodsight.com/biomarkers/cea): CEA monitors a cancer that's already known, it doesn't find it. Why smokers run higher, why one value is noise, and why the post-treatment trend matters.
- [Free PSA](https://bloodsight.com/biomarkers/free-psa): Free PSA is the one free fraction where more is better. How the percent-free ratio sorts the 4-10 PSA gray zone, and why low free PSA is the worrying sign.

### Autoimmune Panel

- [Rheumatoid Factor (RF)](https://bloodsight.com/biomarkers/rheumatoid-factor): A positive rheumatoid factor turns up in healthy people, hepatitis C, lupus and more. What RF tells you, the numbers, and why it can't diagnose RA alone.
- [Anti-Cyclic Citrullinated Peptide (Anti-CCP)](https://bloodsight.com/biomarkers/anti-ccp): Anti-CCP can turn positive years before the first swollen joint. What a positive, negative, or borderline result means for rheumatoid arthritis.
- [Complement C3 (C3)](https://bloodsight.com/biomarkers/complement-c3): Complement C3 is read with anti-dsDNA and C4: as the antibody climbs and complement sinks, the pair flags a lupus flare. Plus the acute-phase trap.
- [Complement C4 (C4)](https://bloodsight.com/biomarkers/complement-c4): A low complement C4 usually means lupus activity, but a persistently low C4 is also the classic screening clue for hereditary angioedema.
- [p-ANCA (p-ANCA)](https://bloodsight.com/biomarkers/p-anca): A positive p-ANCA names a neighborhood of diseases, not one. Why the perinuclear pattern needs an MPO antibody and often a biopsy before it means anything.
- [c-ANCA (c-ANCA)](https://bloodsight.com/biomarkers/c-anca): A positive c-ANCA is a cytoplasmic glow, not a verdict. See why a PR3 immunoassay and often a biopsy must confirm vasculitis before it's named.
- [Anti-SSA (Ro) Antibodies (Anti-SSA)](https://bloodsight.com/biomarkers/anti-ssa): Anti-SSA can stay silent in the person who has it yet cross the placenta and affect a developing baby's heart. What a positive anti-Ro result really means.
- [Antiphospholipid Antibodies (aPL)](https://bloodsight.com/biomarkers/antiphospholipid-antibodies): A single positive antiphospholipid result is confirmed only ~40% of the time; triple positivity ~98%. Why the profile, not one flag, sets your clot risk.
- [Anticardiolipin Antibodies (aCL)](https://bloodsight.com/biomarkers/anticardiolipin): A positive anticardiolipin test often fades after an infection. Why diagnosis needs two positives 12 weeks apart, and what an antiphospholipid carrier is.
- [Immunoglobulin G (IgG)](https://bloodsight.com/biomarkers/igg): A high immunoglobulin G total can be a harmless polyclonal rise or one monoclonal clone. Only serum protein electrophoresis tells the two shapes apart.
- [Anti-Centromere Antibodies (ACA)](https://bloodsight.com/biomarkers/anti-centromere): A positive anti-centromere antibody with cold, color-changing fingers can forecast limited scleroderma years early. What ACA predicts and why.
- [Anti-Double Stranded DNA (Anti-dsDNA)](https://bloodsight.com/biomarkers/anti-dsdna): Anti-dsDNA is prized for lupus specificity, but CLIFT, Farr, and ELISA score it on different scales. Why a rising titer can be the method, not the disease.
- [Anti-Jo-1 Antibodies (Anti-Jo-1)](https://bloodsight.com/biomarkers/anti-jo-1): A positive anti-Jo-1 reads like a muscle marker, but up to 75% of antisynthetase patients develop lung disease, and the lung is what drives the outlook.
- [Anti-Smith Antibody (Anti-Sm)](https://bloodsight.com/biomarkers/smith-antibody): A negative anti-Smith antibody clears almost nothing, but a positive one after a positive ANA is near-conclusive for lupus. How to read your result.
- [Immunoglobulin A (IgA)](https://bloodsight.com/biomarkers/iga): A low IgA can make a routine celiac antibody test read falsely negative. What IgA deficiency means, the <7 mg/dL cutoff, and the test swap that fixes it.
- [Antinuclear Antibodies (ANA)](https://bloodsight.com/biomarkers/ana): A positive ANA rarely means lupus. What the titer (1:40 vs 1:640) and staining pattern tell you, and why up to 1 in 5 healthy adults test positive.

### Vitamins and Nutrients

- [Vitamin D (25-OH D)](https://bloodsight.com/biomarkers/vitamin-d): What a 25-hydroxy vitamin D result means, ng/mL vs nmol/L conversion, deficiency symptoms and causes, and how to raise low vitamin D safely.
- [Zinc (Zn)](https://bloodsight.com/biomarkers/zinc): A low serum zinc often means an infection moved it into the liver, not that your body is short. How timing, meals, and albumin bend the result.
- [Selenium](https://bloodsight.com/biomarkers/selenium): Selenium has one of the narrowest safe windows of any nutrient: the body needs ~55 mcg a day, and harm starts not far above 400. What a normal level means.
- [Vitamin A](https://bloodsight.com/biomarkers/vitamin-a): A normal vitamin A result can hide a near-empty liver. Why serum retinol stays in range until stores run low, plus the toxicity and pregnancy caveats.
- [Vitamin K](https://bloodsight.com/biomarkers/vitamin-k): A direct vitamin K blood level is rarely ordered and reflects only your last few meals. Prothrombin time is the test that shows if vitamin K is working.
- [Vitamin B1 (Thiamine) (B1)](https://bloodsight.com/biomarkers/vitamin-b1): What a thiamine test measures, why the body holds only days of reserve, why a normal serum level can miss deficiency, and what whole-blood testing shows.
- [Vitamin B2 (Riboflavin) (B2)](https://bloodsight.com/biomarkers/vitamin-b2): Riboflavin activates B6 and folate. A quiet shortfall can drag down your active B6 (PLP) even when B6 intake looks fine. What B2 results mean and why.
- [Vitamin B3 (Niacin) (B3)](https://bloodsight.com/biomarkers/vitamin-b3): A niacin blood level looks like a supply gauge, but your body makes B3 from tryptophan and status shows up in urine, not plasma. What actually counts.
- [Copper (Cu)](https://bloodsight.com/biomarkers/copper): A high copper result rarely means copper excess. How ceruloplasmin, inflammation, estrogen, and zinc move the number, and when low copper matters.
- [1,25-Dihydroxyvitamin D (1,25-OH D)](https://bloodsight.com/biomarkers/calcitriol): Calcitriol (1,25-OH D) is the active vitamin D test, not the one that checks if you're deficient. Why it reads normal when you're low, and what it's for.
- [MTHFR](https://bloodsight.com/biomarkers/mthfr): What an MTHFR gene result means, why C677T and A1298C are so common, and why major medical bodies advise against routine MTHFR testing.
- [Chromium](https://bloodsight.com/biomarkers/chromium): Why a chromium blood result sits near the assay's detection limit, when a high or low number means something, and whether chromium helps blood sugar.
- [Manganese (Mn)](https://bloodsight.com/biomarkers/manganese): A manganese blood test is run to catch overload, not deficiency. What high manganese means, the liver and TPN link, and why a low result rarely matters.
- [Vitamin B12](https://bloodsight.com/biomarkers/vitamin-b12): What a vitamin B12 test measures, why serum B12 can read normal while cells run short, low B12 symptoms and causes, and when MMA confirms a deficiency.
- [Folate](https://bloodsight.com/biomarkers/folate): What a folate test measures, normal serum folate range, why low folate and B12 are read together, and how high folate can mask a B12 deficiency.
- [Vitamin B6](https://bloodsight.com/biomarkers/vitamin-b6): What a vitamin B6 (pyridoxine) result means, the 20-125 nmol/L range, why high-dose supplements can cause nerve damage, and what too-high B6 looks like.
- [Vitamin C (VitC)](https://bloodsight.com/biomarkers/vitamin-c): A plasma vitamin C level tracks what you ate the last few days, not your tissue stores. Why it rises hours after eating, and what 0.2 vs 1.2 mg/dL means.
- [Vitamin E](https://bloodsight.com/biomarkers/vitamin-e): A high alpha-tocopherol often tracks your cholesterol, not antioxidant status. Why labs read it against a lipid ratio that reclassifies half of results.
- [Methylmalonic Acid (MMA)](https://bloodsight.com/biomarkers/methylmalonic-acid): What methylmalonic acid measures, why MMA rises only in true B12 deficiency, the gray-zone B12 it confirms, the kidney caveat, and the normal range.

### Bone Health Panel

- [Parathyroid Hormone (PTH)](https://bloodsight.com/biomarkers/parathyroid-hormone): What a parathyroid hormone (PTH) result means, why a normal PTH can be wrong when calcium is high, what high and low PTH point to, and PTH vs thyroid.
- [P1NP (P1NP)](https://bloodsight.com/biomarkers/p1np): P1NP says nothing about how strong your bones are, only how fast new bone is being built. Why a single value barely matters without a baseline.
- [CTX (CTX)](https://bloodsight.com/biomarkers/ctx): CTX peaks overnight and a meal drops it ~20%, so when you ate and what time you were drawn can move the result more than your bones did. What it means.
- [Bone-Specific Alkaline Phosphatase (BSAP)](https://bloodsight.com/biomarkers/bone-alp): Bone-specific ALP reads how fast bone is being built, not how dense it is. Why it tracks Paget's and osteoporosis treatment, and where liver overlaps.
- [Osteocalcin (OC)](https://bloodsight.com/biomarkers/osteocalcin): Osteocalcin is a bone-formation marker, not a density readout. Why it swings overnight, varies by lab, and lost the reference spot to P1NP.

### Heavy Metals Panel

- [Lead (Pb)](https://bloodsight.com/biomarkers/lead): What a blood lead level measures, why 3.5 µg/dL is a population statistic and not a safe threshold, and why old exposure hides in bone for decades.
- [Mercury (Hg)](https://bloodsight.com/biomarkers/mercury): Blood mercury mostly reads the fish you've eaten lately, not your fillings. Why blood and urine answer different questions, and what a high level means.
- [Arsenic (As)](https://bloodsight.com/biomarkers/arsenic): A high total arsenic result usually counts harmless fish arsenic alongside the toxic form. Why speciation matters and what the numbers mean.

### Allergy Panel

- [Tryptase](https://bloodsight.com/biomarkers/tryptase): Why a normal tryptase can still miss anaphylaxis, how the 1-2 hour timing window works, the 20%+2 acute-vs-baseline rule, and what a high baseline means.
- [Total IgE (IgE)](https://bloodsight.com/biomarkers/ige): Why a high total IgE never names the allergen, why a normal level doesn't rule allergy out, and what eczema, parasites, and ABPA do to the number.

### Cardiac Markers

- [Creatine Kinase-MB (CK-MB)](https://bloodsight.com/biomarkers/ck-mb): A high CK-MB can come from a bruised muscle or a hard workout, not just the heart. Why the relative index, not the raw value, tells the difference.
- [Lipoprotein-Associated Phospholipase A2 (Lp-PLA2)](https://bloodsight.com/biomarkers/lp-pla2): A high Lp-PLA2 can mean a large LDL convoy, not active plaque. The 225 PLAC cutoff, why it fades after adjusting for cholesterol, and the STABILITY trial.
- [B-Type Natriuretic Peptide (BNP)](https://bloodsight.com/biomarkers/bnp): Why a rising BNP on heart-failure treatment can mean the drug is working, why obesity hides a high value, and what 100 vs 400 pg/mL really tells you.
- [Myoglobin](https://bloodsight.com/biomarkers/myoglobin): Myoglobin rises first after muscle injury but can't tell heart from hard workout. Why a normal result tells you more than a high one, per ADLM.
- [Troponin (cTn)](https://bloodsight.com/biomarkers/troponin): What a troponin test measures, why high-sensitivity assays find a level in most healthy people, and why a slightly elevated result is not a heart attack.
- [Galectin-3](https://bloodsight.com/biomarkers/galectin-3): Galectin-3 is filed under cardiac markers, but it's a fibrosis protein active in kidney, liver and lung too. Why a high value doesn't name the heart alone.
- [NT-proBNP (NT-proBNP)](https://bloodsight.com/biomarkers/nt-probnp): NT-proBNP rises when the heart wall stretches. A normal result helps rule out heart failure in a breathless person; age, kidneys, and obesity bend it. Why.
- [Troponin I (cTnI)](https://bloodsight.com/biomarkers/troponin-i): Troponin I is the troponin most US labs run. Why an hs-cTnI value can't be compared between hospitals, and why men and women have different cutoffs.
- [Troponin T (cTnT)](https://bloodsight.com/biomarkers/troponin-t): Troponin T comes from one maker, so values compare across labs, but it runs high in kidney and muscle disease. What a steady, mild cTnT elevation means.
- [Homocysteine](https://bloodsight.com/biomarkers/homocysteine): What a homocysteine test measures, the 5-15 umol/L range, why high homocysteine points to B vitamins, the MTHFR question, and the heart-risk disconnect.

### Coagulation Panel

- [Prothrombin Time (PT)](https://bloodsight.com/biomarkers/prothrombin-time): What prothrombin time measures in seconds, why the same blood gives different PT at different labs, and how a stretched PT can flag a failing liver early.
- [Thrombin Time (TT)](https://bloodsight.com/biomarkers/thrombin-time): A prolonged thrombin time reads like a clotting flaw, but a trace of heparin from the draw line is the most common reason the result is off, not the body.
- [Protein C](https://bloodsight.com/biomarkers/protein-c): What a low protein C result means, why warfarin and an active clot make it look falsely low, and the timing rule for an accurate retest.
- [Factor V Leiden](https://bloodsight.com/biomarkers/factor-v-leiden): Factor V Leiden is the inherited clotting result people fear most. Only about 10% of carriers ever clot. The real heterozygous vs homozygous risk.
- [Factor VIII (FVIII)](https://bloodsight.com/biomarkers/factor-viii): A high factor VIII reading often reflects a passing surge from inflammation, stress, or illness, not a lasting clotting disorder. What the percent means.
- [Lupus Anticoagulant (LA)](https://bloodsight.com/biomarkers/lupus-anticoagulant): Lupus anticoagulant prolongs clotting in the tube yet pushes the body toward clots. What a positive means, the 12-week repeat rule, and carrier status.
- [Von Willebrand Factor (VWF)](https://bloodsight.com/biomarkers/von-willebrand-factor): A low VWF result often tracks your blood type, not a bleeding disorder. Why type O runs lower, what the 30-50 gray zone means, and when it matters.
- [Antithrombin III (AT III)](https://bloodsight.com/biomarkers/antithrombin): Low antithrombin isn't a simple on/off clot alarm. See why activity just under 90% barely moves the risk while 60% or lower changes everything.
- [International Normalized Ratio (INR)](https://bloodsight.com/biomarkers/inr): What INR measures, why a healthy person sits near 1.0 while warfarin patients aim for 2.0–3.0, what pushes it out of range, and why DOACs skip it.
- [Activated Partial Thromboplastin Time (aPTT)](https://bloodsight.com/biomarkers/aptt): aPTT times the intrinsic clotting pathway and monitors heparin. Why a long aPTT can mean clotting risk, not bleeding, and what a mixing study finds.
- [Fibrinogen](https://bloodsight.com/biomarkers/fibrinogen): Fibrinogen is the liver's clotting protein and an inflammation marker at once. What low means, why high gets ordered, and how 200-400 mg/dL is read.
- [D-dimer](https://bloodsight.com/biomarkers/d-dimer): D-dimer is sensitive but not specific. A negative result helps rule out a clot in low-risk people; a high one means little alone. Why, and the units trap.

### Thyroid Panel

- [Free Thyroxine (FT4)](https://bloodsight.com/biomarkers/free-t4): Free T4 normal range is 0.8-1.8 ng/dL (10.3-23.2 pmol/L). Unit conversion, biotin interference, pregnancy ranges and levothyroxine dose timing.
- [Thyroid-Stimulating Hormone (TSH)](https://bloodsight.com/biomarkers/tsh): What TSH measures, the normal range, why high TSH means an underactive thyroid (and low means overactive), and what to do about borderline results.
- [Total Thyroxine (T4)](https://bloodsight.com/biomarkers/total-t4): What Total T4 measures, the normal range, why estrogen and pregnancy raise it without thyroid disease, and why labs largely replaced it with Free T4.
- [Anti-Thyroid Peroxidase Antibodies (Anti-TPO)](https://bloodsight.com/biomarkers/anti-tpo): What positive anti-TPO antibodies mean, why a high titer doesn't grade severity, why TSH can stay normal for years, and how monitoring works.
- [Anti-Thyroglobulin Antibodies (TgAb)](https://bloodsight.com/biomarkers/anti-thyroglobulin): What positive anti-thyroglobulin (TgAb) antibodies mean, why a doctor may shrug when anti-TPO is negative, and why TgAb matters in cancer follow-up.
- [Thyroglobulin (Tg)](https://bloodsight.com/biomarkers/thyroglobulin): Why a thyroglobulin level is nearly uninterpretable with an intact thyroid but a clean tumor marker after thyroidectomy, and what 'detectable' means.
- [Thyroxine-Binding Globulin (TBG)](https://bloodsight.com/biomarkers/thyroid-binding-globulin): What thyroxine-binding globulin (TBG) measures, why estrogen and pregnancy raise it, how it explains a misleading total T4, and why it's rarely needed.
- [Free Triiodothyronine (Free T3)](https://bloodsight.com/biomarkers/free-t3): Free T3 normal range is 2.3-4.2 pg/mL (3.5-6.5 pmol/L). Low T3 from fasting and illness (euthyroid sick syndrome) versus true thyroid disease.
- [Reverse Triiodothyronine (rT3)](https://bloodsight.com/biomarkers/reverse-t3): What reverse T3 measures, why it rises during illness and fasting, and the high rT3 ratio debate between endocrinology and functional medicine.

### Diabetes Panel

- [Estimated Average Glucose (eAG)](https://bloodsight.com/biomarkers/estimated-average-glucose): eAG is your HbA1c translated into mg/dL by a formula, not a measured blood sugar. Why it rarely matches your meter average, and the A1C-to-eAG table.
- [Hemoglobin A1c (HbA1c)](https://bloodsight.com/biomarkers/hba1c): What HbA1c measures, normal ranges in % and mmol/mol, why fasting can't improve it, and when anemia or iron deficiency makes the number unreliable.
- [Beta-Hydroxybutyrate (BHB)](https://bloodsight.com/biomarkers/beta-hydroxybutyrate): The blood BHB test and the urine strip chase two different ketones. Why the strip lags a fast climb, reads worse in recovery, and what 1.6 mmol/L means.
- [Glycated Albumin (GA)](https://bloodsight.com/biomarkers/glycated-albumin): Glycated albumin is a percentage that can move when your albumin changes, even with steady blood sugar. Why thyroid, liver, and kidney conditions shift GA.
- [Fasting Glucose](https://bloodsight.com/biomarkers/fasting-glucose): What 'fasting' means before a glucose test, what quietly breaks it (coffee, gum, a short fast), and why a fasted number says more than a random one.
- [Insulin](https://bloodsight.com/biomarkers/insulin): What fasting insulin measures, why it can run high for years while glucose stays normal, how HOMA-IR is built from it, and why labs disagree on the range.
- [C-Peptide](https://bloodsight.com/biomarkers/c-peptide): What C-peptide measures, why doctors count it instead of insulin, the typical 0.8–3.8 ng/mL range, and how it tells homemade insulin from injected.
- [HOMA-IR (HOMA-IR)](https://bloodsight.com/biomarkers/homa-ir): HOMA-IR is a 1985 formula, not a test: glucose times insulin over a constant. What the score means, why thresholds run 1.9 to 2.9, and what it inherits.
- [Fructosamine](https://bloodsight.com/biomarkers/fructosamine): Fructosamine is a 2-3 week glucose average read off blood proteins, not red cells. Why it's used when HbA1c lies, its range, and where it falls apart.

### Hormone Panel

- [DHEA-Sulfate (DHEA-S)](https://bloodsight.com/biomarkers/dhea-s): DHEA-S is the one adrenal hormone you can draw at any hour and still trust. What high and low levels mean by age and sex, and why supplements rarely help.
- [Sex Hormone-Binding Globulin (SHBG)](https://bloodsight.com/biomarkers/shbg): What SHBG measures, why it's drawn to interpret a total testosterone, what high and low SHBG mean, and how it links to insulin resistance and PCOS.
- [Testosterone](https://bloodsight.com/biomarkers/testosterone): What total testosterone measures, normal ranges for men and women, why a morning draw matters, and what the total leaves out about the usable hormone.
- [Calcitonin](https://bloodsight.com/biomarkers/calcitonin): Calcitonin is named for calcium but ordered as a thyroid tumor marker. Why a high or rising result points at C cells, not your calcium.
- [Inhibin B](https://bloodsight.com/biomarkers/inhibin-b): Inhibin B is the signal that brakes FSH, so a falling inhibin B is mirrored by a rising FSH. Read the two as a pair, never alone.
- [Pregnenolone](https://bloodsight.com/biomarkers/pregnenolone): Pregnenolone is sold for memory and anti-aging, but the one human trial found no benefit. What a level means, when it's ordered, and why context matters.
- [Aldosterone](https://bloodsight.com/biomarkers/aldosterone): Aldosterone controls the salt and water your body keeps. Read against renin, it can reveal primary aldosteronism behind blood pressure that won't budge.
- [Insulin-Like Growth Factor 1 (IGF-1)](https://bloodsight.com/biomarkers/igf-1): Why doctors read IGF-1 instead of growth hormone, why a 'low' often just means you got older, and why higher isn't healthier.
- [Growth Hormone (GH)](https://bloodsight.com/biomarkers/growth-hormone): Why a single growth hormone reading is uninterpretable, and how a glucose drink or a stimulating drug forces the answer the resting number hides.
- [Renin](https://bloodsight.com/biomarkers/renin): A renin level read alone tells you almost nothing. See the supine vs standing ranges, the aldosterone-to-renin ratio cutoff, and how to prep the draw.
- [17-Hydroxyprogesterone (17-OHP)](https://bloodsight.com/biomarkers/17-hydroxyprogesterone): A high 17-OHP isn't a hormone running wild. It's a precursor backing up behind one blocked enzyme. What the 200 and 1000 ng/dL cutoffs mean.
- [Androstenedione](https://bloodsight.com/biomarkers/androstenedione): Androstenedione sits between two famous hormones. Its value is positional: it flags an overproducing steroid line and tracks adrenal disease in both sexes.
- [Free Testosterone](https://bloodsight.com/biomarkers/free-testosterone): What free testosterone measures, why low free T can explain symptoms when total looks normal, and why calculated free T beats the direct assay.
- [Estradiol (E2)](https://bloodsight.com/biomarkers/estradiol): Why an estradiol level can swing tenfold across one cycle and stay normal, what high and low E2 point to, and why men's estradiol matters for bone.
- [Progesterone](https://bloodsight.com/biomarkers/progesterone): Why a progesterone level only means something seven days after ovulation, why the day-21 rule misfires, and what high and low results actually point to.
- [Luteinizing Hormone (LH)](https://bloodsight.com/biomarkers/luteinizing-hormone): Why a single LH reading catches a pulsing signal mid-sweep, how the mid-cycle surge triggers ovulation, and how LH plus FSH locates a hormone problem.
- [Cortisol](https://bloodsight.com/biomarkers/cortisol): Why a cortisol result means little without the draw time, what high and low cortisol screen for, and why a single morning level rarely measures stress.
- [Prolactin (PRL)](https://bloodsight.com/biomarkers/prolactin): Why a mildly high prolactin is often stress, a medication, or the macroprolactin artifact rather than a tumor, plus what low and high PRL really mean.
- [Follicle-Stimulating Hormone (FSH)](https://bloodsight.com/biomarkers/fsh): What FSH measures, why a day-3 draw matters, what high FSH says about menopause and ovarian reserve, and why it is read beside LH and estradiol.
- [Anti-Müllerian Hormone (AMH)](https://bloodsight.com/biomarkers/amh): What AMH actually measures, why a low result does not mean you can't conceive, why it runs high in PCOS, and the one question it answers well.
- [Adrenocorticotropic Hormone (ACTH)](https://bloodsight.com/biomarkers/acth): Why ACTH is rarely drawn alone, how high and low ACTH paired with cortisol point to the pituitary or the adrenal glands, and what the result locates.

### Complete Blood Count (CBC)

- [Hemoglobin (Hgb)](https://bloodsight.com/biomarkers/hemoglobin): What hemoglobin measures, normal ranges for men and women, why dehydration fakes a high reading, and why a normal Hgb can still hide low iron.
- [White Blood Cell Count (WBC)](https://bloodsight.com/biomarkers/white-blood-cell-count): What a high or low white blood cell count means, why exercise, stress, smoking and steroids raise it without infection, and why the differential matters.
- [Red Blood Cell Count (RBC)](https://bloodsight.com/biomarkers/red-blood-cell-count): RBC normal range, what high and low red blood cell count mean, and why the count can read high while you're anemic. How it reads beside hemoglobin and MCV.
- [Neutrophils](https://bloodsight.com/biomarkers/neutrophils): Neutrophils are more than half the white count, so they usually drive it. What low and high mean, demargination, and severe neutropenia vs Duffy-null.
- [Hematocrit (Hct)](https://bloodsight.com/biomarkers/hematocrit): What hematocrit measures, normal ranges for men and women, why dehydration fakes a high reading, and why the CBC carries three red-cell numbers at once.
- [Platelet Count (PLT)](https://bloodsight.com/biomarkers/platelet-count): What the platelet count measures, the 150–450 normal range, why a low PLT can be a lab artifact, and what high and low platelets actually mean.
- [Mean Corpuscular Volume (MCV)](https://bloodsight.com/biomarkers/mean-corpuscular-volume): What MCV measures, the 80-100 fL normal range, why small cells point to iron and large cells to B12, and how a normal MCV can hide a mixed deficiency.
- [Mean Platelet Volume (MPV)](https://bloodsight.com/biomarkers/mean-platelet-volume): What MPV measures, the ~7.5–11.5 fL range, why a high MPV often means fresh platelets replacing losses, and why a low MPV hints at a production problem.
- [Mean Corpuscular Hemoglobin (MCH)](https://bloodsight.com/biomarkers/mean-corpuscular-hemoglobin): What MCH measures, the 27-33 pg normal range, why it almost always echoes MCV, how it differs from MCHC, and when a high MCH is real vs a lab artifact.
- [Mean Corpuscular Hemoglobin Concentration (MCHC)](https://bloodsight.com/biomarkers/mchc): What MCHC measures, the 32-36 g/dL range, why a high MCHC usually means a lab artifact or spherocytosis, how low MCHC tracks iron, and MCHC vs MCH.
- [Red Cell Distribution Width (RDW)](https://bloodsight.com/biomarkers/red-cell-distribution-width): What RDW measures, the 11.5-14.5% normal range, why RDW can rise before hemoglobin or MCV change, and how it splits iron deficiency from thalassemia.
- [Reticulocytes (Retic)](https://bloodsight.com/biomarkers/reticulocytes): What the reticulocyte count measures, why a high retic in anemia means the marrow is keeping pace, and why a low one means the pipeline has stalled.
- [Lymphocytes](https://bloodsight.com/biomarkers/lymphocytes): Why a virus lifts lymphocytes while the WBC total barely moves, why 'atypical lymphocytes' on a mono report are benign, and when a high count matters.
- [Monocytes](https://bloodsight.com/biomarkers/monocytes): Why a monocyte count is a snapshot of cells in transit, what high (monocytosis) and low monocytes mean, and why the count is read across the differential.
- [Eosinophils](https://bloodsight.com/biomarkers/eosinophils): Why eosinophils climb in hay-fever season, asthma, and parasites, why a normal count never rules an allergy in or out, and when a high count needs a look.
- [Basophils](https://bloodsight.com/biomarkers/basophils): Basophils are the rarest white cell, often reported as zero. Why a low count means little, and why a persistent high (basophilia) is the signal to check.

### Inflammation Markers

- [Procalcitonin (PCT)](https://bloodsight.com/biomarkers/procalcitonin): Procalcitonin is the inflammation marker doctors use to decide when to stop antibiotics, not start them. What high, slight, and falling PCT levels mean.
- [Serum Amyloid A (SAA)](https://bloodsight.com/biomarkers/serum-amyloid-a): Why serum amyloid A can jump a thousandfold for the same illness that moves CRP modestly, what a sky-high SAA number means, and the amyloidosis link.
- [Calprotectin](https://bloodsight.com/biomarkers/calprotectin): A low calprotectin rules gut inflammation out and a high one flags it, but the wide 50-250 middle band answers almost nothing. Here is why.
- [High-Sensitivity C-Reactive Protein (hs-CRP)](https://bloodsight.com/biomarkers/hs-crp): hs-CRP reads the same protein as CRP at a finer setting. The AHA/CDC <1, 1–3, >3 mg/L risk tiers, why a cold ruins the reading, and when to use which.
- [C-Reactive Protein (CRP)](https://bloodsight.com/biomarkers/crp): What a high CRP means, why it can't say where inflammation is, the mg/L vs mg/dL trap, and how standard CRP differs from hs-CRP for heart risk.
- [Erythrocyte Sedimentation Rate (ESR)](https://bloodsight.com/biomarkers/esr): What ESR measures, the normal range by sex, why high ESR is nonspecific, what raises it without inflammation, and why it lags and lingers behind CRP.

### Kidney Function Panel

- [Microalbumin](https://bloodsight.com/biomarkers/microalbumin): Microalbumin can flag kidney trouble while eGFR and creatinine read normal. What an albumin-to-creatinine ratio over 30 mg/g means, and what it doesn't.
- [Beta-2 Microglobulin (B2M)](https://bloodsight.com/biomarkers/beta-2-microglobulin): A high beta-2 microglobulin can mean more cell turnover or slower kidneys, and the same number stages myeloma. Here's how to tell which is which.
- [Uric Acid](https://bloodsight.com/biomarkers/uric-acid): What uric acid measures, why high levels rarely mean gout, why a normal level during a flare proves nothing, and why kidneys matter more than diet.
- [Cystatin C](https://bloodsight.com/biomarkers/cystatin-c): Cystatin C is a kidney filtration marker that ignores muscle and diet but has its own quirks. What 0.6-1.0 mg/L means and how it checks creatinine.
- [Creatinine Clearance (CrCl)](https://bloodsight.com/biomarkers/creatinine-clearance): Creatinine clearance is the kidney test you collect over 24 hours. Why a missed void throws it off, why it overestimates GFR, and how it differs from eGFR.
- [Albumin-to-Creatinine Ratio (uACR)](https://bloodsight.com/biomarkers/albumin-creatinine-ratio): What the urine albumin-to-creatinine ratio measures, why 30 mg/g matters, how it flags kidney damage before eGFR falls, and why a high result is repeated.
- [BUN-to-Creatinine Ratio (BUN/Cr)](https://bloodsight.com/biomarkers/bun-creatinine-ratio): The BUN:creatinine ratio doesn't grade kidney damage, it locates the cause. Why a high ratio points to dehydration or bleeding, and what 10:1–20:1 means.

### Lipid Panel

- [HDL Cholesterol (HDL)](https://bloodsight.com/biomarkers/hdl-cholesterol): What HDL cholesterol means, the normal range for men and women, why low HDL matters, and why a very high HDL doesn't keep earning extra protection.
- [Total Cholesterol](https://bloodsight.com/biomarkers/total-cholesterol): What total cholesterol measures, what counts as normal, and why a high total driven by high HDL can be healthier than a lower one built from high LDL.
- [LDL Cholesterol (LDL)](https://bloodsight.com/biomarkers/ldl-cholesterol): What LDL cholesterol means, what counts as a normal range, why high LDL matters, and why your report often says 'calculated' instead of measured.
- [Triglycerides](https://bloodsight.com/biomarkers/triglycerides): What triglycerides measure, the normal range, why last night's dinner and alcohol move the number, when high levels point to the pancreas, and fasting.
- [VLDL Cholesterol (VLDL)](https://bloodsight.com/biomarkers/vldl-cholesterol): VLDL is the lipid-panel line nobody explains. Why it's just triglycerides divided by 5, what a high VLDL means, and when the number is safe to skip.
- [Apolipoprotein B (ApoB)](https://bloodsight.com/biomarkers/apolipoprotein-b): What apolipoprotein B (ApoB) means, what a normal range looks like, and why two people with identical LDL can carry very different particle counts.
- [Lipoprotein(a) (Lp(a))](https://bloodsight.com/biomarkers/lipoprotein-a): What lipoprotein(a) means, why Lp(a) is mostly inherited, why it isn't on a standard lipid panel, and why mg/dL and nmol/L don't convert cleanly.
- [Apolipoprotein A-1 (ApoA-1)](https://bloodsight.com/biomarkers/apolipoprotein-a1): What apolipoprotein A-1 (ApoA-1) is, a typical normal range, what low ApoA-1 means, and why the apoB/apoA-1 ratio matters more than the value alone.
- [Non-HDL Cholesterol](https://bloodsight.com/biomarkers/non-hdl-cholesterol): Non-HDL cholesterol is total cholesterol minus HDL. What a healthy level is, why it needs no fasting, and why it holds up when calculated LDL wobbles.
- [Total Cholesterol to HDL Ratio](https://bloodsight.com/biomarkers/cholesterol-hdl-ratio): The total cholesterol to HDL ratio on your lipid panel: what bands like under 3.5 and 5 mean, why guidelines now look past it, and what it still catches.

### Liver Function Panel

- [Lipase](https://bloodsight.com/biomarkers/lipase): Lipase can stay high for days after amylase returns to normal. See what a high lipase means, when it points to pancreatitis, and its other causes.
- [Lactate Dehydrogenase (LDH)](https://bloodsight.com/biomarkers/ldh): A high LDH means a cell broke somewhere, not which organ. Why the test is so nonspecific, how isoenzymes localize the source, and what raises it.
- [5'-Nucleotidase (5-NT)](https://bloodsight.com/biomarkers/five-prime-nucleotidase): A high alkaline phosphatase can come from liver or bone. 5'-nucleotidase is the enzyme labs use to name the source. What high and normal results mean.
- [Ammonia](https://bloodsight.com/biomarkers/ammonia): Ammonia keeps rising in the tube after the draw, doubling within about two hours off ice. Why a high reading is often handling, not your liver.
- [Ceruloplasmin](https://bloodsight.com/biomarkers/ceruloplasmin): Ceruloplasmin is a copper-carrying protein and an acute-phase reactant that can read normal in Wilson disease. What low, normal, and high values mean.
- [Alpha-1 Antitrypsin (A1AT)](https://bloodsight.com/biomarkers/alpha-1-antitrypsin): Why a normal alpha-1 antitrypsin level can mask an inherited deficiency, what a low result means for lungs and liver, and the 1–2.5 g/L reference range.
- [Amylase](https://bloodsight.com/biomarkers/amylase): A high amylase points at the pancreas, but salivary glands, the gut, kidneys, and macroamylasemia move the same number. How to read the result.
- [Indirect Bilirubin](https://bloodsight.com/biomarkers/bilirubin-indirect): A high indirect bilirubin can mean red cells breaking down too fast or a liver that conjugates slowly. Why it's calculated, and how to tell the two apart.
- [Alanine Aminotransferase (ALT)](https://bloodsight.com/biomarkers/alt): What an ALT blood test measures: a liver damage marker, not a function test. Why fatty liver, exercise, and some medicines raise it, plus ALT vs AST.
- [Aspartate Aminotransferase (AST)](https://bloodsight.com/biomarkers/ast): What an AST blood test measures, why a high AST points at the liver, heart, muscle, or red cells at once, and why the AST:ALT ratio decides what it means.
- [Gamma-Glutamyl Transferase (GGT)](https://bloodsight.com/biomarkers/ggt): What a GGT test measures, why a high gamma-glutamyl transferase points at the liver or bile ducts rather than bone, and its limits as an alcohol marker.
- [Alkaline Phosphatase (ALP)](https://bloodsight.com/biomarkers/alkaline-phosphatase): What an ALP blood test measures, why a high alkaline phosphatase could come from the liver or the bones, and why a child's high ALP is usually normal.
- [Total Bilirubin](https://bloodsight.com/biomarkers/bilirubin-total): What high total bilirubin means, the 0.2–1.2 mg/dL normal range, and why the most common high result (Gilbert's syndrome) needs nothing at all.
- [Direct Bilirubin (Direct Bili)](https://bloodsight.com/biomarkers/bilirubin-direct): What high direct (conjugated) bilirubin means, the 0–0.3 mg/dL range, why it points to bile ducts and obstruction, and the dark-urine tell.
- [Haptoglobin](https://bloodsight.com/biomarkers/haptoglobin): What low haptoglobin means, why it falls during hemolysis instead of rising, the 30–200 mg/dL range, and how inflammation can hide a true drop.

### Comprehensive Metabolic Panel (CMP)

- [Calcium (Ca)](https://bloodsight.com/biomarkers/calcium): What a serum calcium result means, why low albumin fakes a low number, how corrected and ionized calcium work, and what a true abnormal value points to.
- [Anion Gap](https://bloodsight.com/biomarkers/anion-gap): The anion gap is calculated, not measured: sodium minus chloride and bicarbonate. What high and low mean, and why low albumin can hide a real acidosis.
- [Glucose](https://bloodsight.com/biomarkers/glucose): What glucose measures on a metabolic panel, the normal fasting range, why a non-fasting result reads high, and how to convert mg/dL to mmol/L.
- [Lactate](https://bloodsight.com/biomarkers/lactate): A clenched fist, a slow tourniquet, or a recent workout can push lactate high in a healthy person. How to tell a real elevation from a faked one.
- [Creatinine](https://bloodsight.com/biomarkers/creatinine): What creatinine measures, why muscle mass and diet move the number, how eGFR is built from it, and why a normal result can hide failing kidneys.
- [Blood Urea Nitrogen (BUN)](https://bloodsight.com/biomarkers/blood-urea-nitrogen): What blood urea nitrogen measures, why high BUN with normal creatinine usually isn't kidneys, the BUN:creatinine ratio, and the mg/dL vs urea mmol/L trap.
- [Estimated Glomerular Filtration Rate (eGFR)](https://bloodsight.com/biomarkers/egfr): What eGFR actually measures, why no instrument read it, why 59 and 61 sit on opposite sides of a stage line, and what the 2021 race-free formula changed.
- [Sodium (Na)](https://bloodsight.com/biomarkers/sodium): What sodium measures, why a low result is almost always too much water rather than too little salt, the narrow 135-145 mmol/L range, and what high means.
- [Potassium (K)](https://bloodsight.com/biomarkers/potassium): What potassium measures, why a surprise high is often a hemolyzed sample not your heart, what really moves the number, and the narrow range that matters.
- [Chloride (Cl)](https://bloodsight.com/biomarkers/chloride): What chloride measures, why it mostly shadows sodium, how it feeds the anion gap that flags an unmeasured acid, and what high or low chloride means.
- [Carbon Dioxide (CO₂)](https://bloodsight.com/biomarkers/carbon-dioxide): The CO₂ on a metabolic panel is mostly bicarbonate, the blood's main acid buffer, not the gas you breathe out. What high and low levels usually mean.
- [Albumin](https://bloodsight.com/biomarkers/albumin): What albumin measures, why low albumin usually points to inflammation, liver, or kidney loss rather than diet, the 3.5–5.0 g/dL range, and what high means.
- [Total Protein](https://bloodsight.com/biomarkers/total-protein): Total protein is albumin plus all the globulins added up. Why a high or low result means little until you know which fraction moved, plus the A/G ratio.
- [Magnesium (Mg)](https://bloodsight.com/biomarkers/magnesium): What a serum magnesium result means, the 1.7–2.2 mg/dL range, why a normal number can miss true depletion, who runs low, and what raises it.
- [Globulin](https://bloodsight.com/biomarkers/globulin): Globulin is calculated as total protein minus albumin. What high and low mean, the A/G ratio, the 2.0–3.5 g/dL range, and when electrophoresis follows.
- [Phosphorus (P)](https://bloodsight.com/biomarkers/phosphorus): What a serum phosphorus result means, the 2.5–4.5 mg/dL range, why high phosphate points to the kidneys, what drops it, and why it mirrors calcium.
- [Creatine Kinase (CK)](https://bloodsight.com/biomarkers/creatine-kinase): What a creatine kinase test measures, why exercise and muscle mass raise CK, how it differs from creatinine, and when a high number means rhabdomyolysis.

## Biomarker comparisons

- [All comparisons](https://bloodsight.com/compare): Index of side-by-side biomarker pairs.
- [Hemoglobin vs Hematocrit](https://bloodsight.com/compare/hemoglobin-vs-hematocrit): Hemoglobin reports the oxygen-carrying protein concentration; hematocrit reports the share of blood made of red cells. See how Hgb and Hct read on a CBC.
- [Total Cholesterol vs HDL](https://bloodsight.com/compare/total-cholesterol-vs-hdl): Understand cholesterol HDL ratio meaning and what total cholesterol/HDL numbers may indicate. See how to calculate the ratio and read it on a lipid panel.
- [Triglycerides vs HDL](https://bloodsight.com/compare/triglycerides-vs-hdl): The triglyceride/HDL ratio (TG/HDL) is one of the better-known insulin-resistance proxies on a lipid panel. See what it captures and how TG and HDL compare.
- [Hemoglobin vs RBC Count](https://bloodsight.com/compare/hemoglobin-vs-red-blood-cell-count): Hemoglobin tracks oxygen-carrying protein concentration; RBC count tracks the number of red blood cells. See how Hgb and RBC read together on a CBC report.
- [MCV vs MCH](https://bloodsight.com/compare/mcv-vs-mch-vs-mchc): MCV reports red cell size, MCH reports hemoglobin per cell, MCHC reports hemoglobin concentration in the cell. See how all three CBC indices read together.
- [TSH vs Free T4](https://bloodsight.com/compare/tsh-vs-free-t4): TSH is the pituitary signal asking for thyroid hormone; free T4 is the thyroid's main output. See how the feedback loop reads on a thyroid panel.
- [TSH vs Free T3](https://bloodsight.com/compare/tsh-vs-free-t3): TSH is the pituitary signal; free T3 is the active thyroid hormone. See how TSH and free T3 read together and what each reflects on a thyroid panel.
- [Free T4 vs Total T4](https://bloodsight.com/compare/free-t4-vs-total-t4): Free T4 measures the unbound, active fraction; total T4 includes both bound and unbound thyroxine. See how the two values read on a thyroid panel.
- [ALT vs AST](https://bloodsight.com/compare/alt-vs-ast): ALT is liver-specific; AST is also present in muscle and other tissues. See how ALT and AST read together on a liver panel and what their ratio reflects.
- [ALT vs GGT](https://bloodsight.com/compare/alt-vs-ggt): ALT reflects liver cell content; GGT reflects membrane-tied bile activity. See how ALT and GGT read together on a liver panel and how they differ.
- [Total vs Direct Bilirubin](https://bloodsight.com/compare/bilirubin-total-vs-direct): Total bilirubin is the sum of all forms; direct (conjugated) bilirubin is the water-soluble fraction. See how the two read together on a liver panel.
- [LDL vs HDL](https://bloodsight.com/compare/ldl-vs-hdl): Understand the LDL/HDL ratio, how it's used to assess cardiovascular risk, and ways to improve it. See LDL/HDL alongside total cholesterol on a panel.
- [Total Cholesterol vs LDL](https://bloodsight.com/compare/total-cholesterol-vs-ldl): Total cholesterol sums every cholesterol fraction; LDL is one of those fractions. See how total cholesterol and LDL relate and read on a lipid panel.
- [Triglycerides vs Cholesterol](https://bloodsight.com/compare/triglycerides-vs-cholesterol): Triglycerides transport storage fat; total cholesterol sums all cholesterol fractions. See how triglycerides and cholesterol read together on a lipid panel.
- [HbA1c vs Fasting Glucose](https://bloodsight.com/compare/hba1c-vs-fasting-glucose): HbA1c reflects 2–3 month average glucose exposure; fasting glucose is a same-moment snapshot. See how HbA1c and fasting glucose read together on a panel.
- [Insulin vs C-Peptide](https://bloodsight.com/compare/insulin-vs-c-peptide): Insulin is the hormone itself; C-peptide is the fragment released alongside insulin during pancreatic secretion. See how the two read on a diabetes panel.
- [HbA1c vs Glucose](https://bloodsight.com/compare/hba1c-vs-glucose): HbA1c is reported as a percentage reflecting long-term glucose; glucose is the current blood sugar value. See how HbA1c and glucose read together.
- [BUN vs Creatinine](https://bloodsight.com/compare/bun-vs-creatinine): BUN reflects urea nitrogen from protein metabolism; creatinine reflects muscle turnover. See how BUN and creatinine read together and the BUN/Cr ratio.
- [Creatinine vs eGFR](https://bloodsight.com/compare/creatinine-vs-egfr): Creatinine is the directly measured value; eGFR is the calculated kidney filtration rate from creatinine, age, and sex. See how the two read on a panel.
- [Ferritin vs Iron](https://bloodsight.com/compare/ferritin-vs-iron): Ferritin reflects stored iron; serum iron reflects what's currently circulating. See how ferritin and iron read together on an iron studies panel.
- [Iron vs TIBC](https://bloodsight.com/compare/iron-vs-tibc): Iron measures the circulating amount; TIBC measures the blood's total iron-binding capacity. See how the two read on an iron studies panel.
- [Ferritin vs Transferrin](https://bloodsight.com/compare/ferritin-vs-transferrin): Ferritin reflects iron storage; transferrin is the transport protein carrying iron. See how ferritin and transferrin read together on an iron studies panel.
- [CRP vs ESR](https://bloodsight.com/compare/crp-vs-esr): CRP rises within hours and falls within days; ESR moves on a slower days-to-weeks timescale. See how CRP and ESR read together on a panel.
- [CRP vs hs-CRP](https://bloodsight.com/compare/crp-vs-hs-crp): Both measure the same blood protein but at different sensitivity scales — standard CRP for visible inflammation, hs-CRP for fine cardiovascular detection.
- [Troponin I vs Troponin T](https://bloodsight.com/compare/troponin-i-vs-troponin-t): Troponin I and troponin T are two cardiac troponin proteins measured separately on a cardiac panel. See how cTnI and cTnT read together and how they differ.
- [BNP vs NT-proBNP](https://bloodsight.com/compare/bnp-vs-nt-probnp): BNP is the active hormone fragment; NT-proBNP is the inactive precursor fragment. See how BNP and NT-proBNP read on a cardiac panel and how they differ.
- [Total vs Free Testosterone](https://bloodsight.com/compare/testosterone-vs-free-testosterone): Total testosterone reports the full hormone level; free testosterone reports the unbound, biologically active fraction. See how the two read together.
- [LH vs FSH](https://bloodsight.com/compare/lh-vs-fsh): LH and FSH are both pituitary hormones in IU/L driving gonadal function. See how LH and FSH read together on a hormone panel and what their pattern reflects.
- [Folate vs Vitamin B12](https://bloodsight.com/compare/folate-vs-b12): Folate and vitamin B12 are reviewed together because both affect red cell formation and the same metabolic pathways. See how folate and B12 read on a panel.
- [PT vs aPTT](https://bloodsight.com/compare/pt-vs-aptt): PT measures the extrinsic clotting pathway in seconds; aPTT measures the intrinsic pathway. See how PT and aPTT read together on a coagulation panel.
- [PT vs INR](https://bloodsight.com/compare/pt-vs-inr): PT is reported in seconds; INR is the standardized ratio derived from PT for cross-lab comparability. See how PT and INR read on a coagulation panel.
- [Hemoglobin vs Ferritin](https://bloodsight.com/compare/hemoglobin-vs-ferritin): Hemoglobin reflects oxygen-carrying capacity; ferritin reflects how much iron is stored. See how Hgb and ferritin read across CBC and iron panels.
- [Neutrophils vs Lymphocytes](https://bloodsight.com/compare/neutrophils-vs-lymphocytes): Neutrophils handle bacterial response; lymphocytes drive adaptive immunity. See how the two largest WBC subsets read together on a CBC report.
- [WBC vs Neutrophils](https://bloodsight.com/compare/wbc-vs-neutrophils): WBC reports the total white blood cell count; neutrophils report just the largest WBC subset. See how WBC and neutrophils relate on a CBC report.
- [MCV vs RDW](https://bloodsight.com/compare/mcv-vs-rdw): MCV shows the average size of red blood cells; RDW shows how much red cells vary in size. See how MCV and RDW read alongside hemoglobin on a CBC report.
- [Reticulocytes vs Hemoglobin](https://bloodsight.com/compare/reticulocytes-vs-hemoglobin): Reticulocytes count newly released red blood cells; hemoglobin shows oxygen-carrying capacity. See how the two read together on a CBC report.
- [Lymphocytes vs Monocytes](https://bloodsight.com/compare/lymphocytes-vs-monocytes): Lymphocytes drive adaptive immune response; monocytes are the cleanup-and-response subset. See how lymphocytes and monocytes read together on a CBC.
- [LDL vs ApoB](https://bloodsight.com/compare/ldl-vs-apob): LDL measures cholesterol concentration in LDL particles; ApoB counts the particles themselves. See how LDL and ApoB read together on a lipid panel.
- [LDL vs Non-HDL Cholesterol](https://bloodsight.com/compare/ldl-vs-non-hdl-cholesterol): LDL reports a single cholesterol fraction; non-HDL is total cholesterol minus HDL. See how the two read together and what non-HDL adds on a lipid panel.
- [Lp(a) vs LDL](https://bloodsight.com/compare/lipoprotein-a-vs-ldl): Lipoprotein(a) is a separate particle type with its own genetic driver; LDL reports a cholesterol fraction. See how Lp(a) and LDL read on a lipid panel.
- [ApoB vs ApoA-1](https://bloodsight.com/compare/apob-vs-apoa1): ApoB is the protein on atherogenic LDL/VLDL particles; ApoA-1 is the protein on HDL. See how ApoB and ApoA-1 read alongside the standard lipid panel.
- [AST vs LDH](https://bloodsight.com/compare/ast-vs-ldh): AST reflects liver and muscle cell content; LDH is a broader cell-turnover enzyme. See how AST and LDH read together and what each value reflects.
- [ALP vs GGT](https://bloodsight.com/compare/alp-vs-ggt): ALP is found in bone and bile; GGT is more bile-specific. See how ALP and GGT read together on a liver panel and what their pattern often reflects.
- [Albumin vs Globulin](https://bloodsight.com/compare/albumin-vs-globulin): Learn what the albumin globulin ratio means and how it relates to key markers like LDL/HDL ratio, TG/HDL ratio, and ApoB/ApoA-1. Interpretation tips.
- [Albumin vs Total Protein](https://bloodsight.com/compare/albumin-vs-total-protein): Albumin is the largest single protein fraction; total protein is the sum of albumin and globulin. See how the two read together on a CMP report.
- [Sodium vs Potassium](https://bloodsight.com/compare/sodium-vs-potassium): Sodium is the main extracellular electrolyte; potassium is the main intracellular one. See how Na and K read together on a metabolic panel report.
- [Sodium vs Chloride](https://bloodsight.com/compare/sodium-vs-chloride): Sodium is the main positive electrolyte; chloride is the main negative one. See how Na and Cl read together and what their gap reflects on a CMP.
- [Calcium vs Phosphorus](https://bloodsight.com/compare/calcium-vs-phosphorus): Calcium and phosphorus are reciprocal minerals regulated together. See how Ca and P read on a metabolic panel and what their balance reflects.
- [Vitamin D vs PTH](https://bloodsight.com/compare/vitamin-d-vs-pth): 25-OH vitamin D reflects circulating storage; PTH regulates calcium and rises when vitamin D is low. See how vitamin D and PTH read together.
- [Calcium vs PTH](https://bloodsight.com/compare/calcium-vs-pth): Calcium is the measured mineral level; PTH is the hormone that regulates it. See how calcium and PTH read together on related lab panels.
- [Homocysteine vs Vitamin B12](https://bloodsight.com/compare/homocysteine-vs-b12): Homocysteine is an amino acid that rises when B12 (or folate) is low; vitamin B12 is the cofactor that lowers it. See how the two read together on a panel.
- [Free T4 vs Free T3](https://bloodsight.com/compare/free-t4-vs-free-t3): Free T4 is the storage form; free T3 is the active thyroid hormone. See how free T4 and free T3 read together and what each reflects on a panel.
- [TSH vs Reverse T3](https://bloodsight.com/compare/tsh-vs-reverse-t3): TSH is the active pituitary signal; reverse T3 (rT3) is the inactive thyroid metabolite. See how TSH and rT3 read together on a thyroid panel.
- [Thyroglobulin vs Anti-Tg](https://bloodsight.com/compare/thyroglobulin-vs-anti-tg): Thyroglobulin (Tg) measures the thyroid-derived protein; Anti-Tg antibodies measure immune binding to it. See how Tg and Anti-Tg read on a thyroid panel.
- [Testosterone vs SHBG](https://bloodsight.com/compare/testosterone-vs-shbg): Testosterone reports the circulating hormone amount; SHBG is the binding protein that carries it. See how testosterone and SHBG read on a hormone panel.
- [Estradiol vs Progesterone](https://bloodsight.com/compare/estradiol-vs-progesterone): Estradiol (E2) and progesterone are two reproductive hormones reviewed across the menstrual cycle. See how E2 and progesterone read on a hormone panel.
- [Cortisol vs ACTH](https://bloodsight.com/compare/cortisol-vs-acth): Cortisol is the adrenal output hormone; ACTH is the pituitary signal that drives cortisol. See how cortisol and ACTH read together on a hormone panel.
- [LH vs Testosterone](https://bloodsight.com/compare/lh-vs-testosterone): LH is the pituitary signal driving testosterone; testosterone is the resulting level. See how LH and testosterone read on a hormone panel.
- [Transferrin vs TIBC](https://bloodsight.com/compare/transferrin-vs-tibc): Transferrin is the iron transport protein measured directly; TIBC is the total binding capacity. See how transferrin and TIBC relate on an iron panel.
- [Iron Saturation vs Ferritin](https://bloodsight.com/compare/iron-saturation-vs-ferritin): Iron saturation (TSAT) reflects how much transferrin carries iron; ferritin reflects storage. See how TSAT and ferritin read on an iron studies panel.
- [Insulin vs HbA1c](https://bloodsight.com/compare/insulin-vs-hba1c): Insulin reports the current circulating hormone level; HbA1c reports long-term glucose exposure. See how insulin and HbA1c read together on a panel.
- [HbA1c vs eAG](https://bloodsight.com/compare/hba1c-vs-estimated-average-glucose): HbA1c is the lab measurement (%); eAG is the calculated average glucose (mg/dL) derived from HbA1c. See how the two report the same trend.

## Learning guides

- [All guides](https://bloodsight.com/learn): Index of lab interpretation guides.
- [Blood Test Results Explained: A Plain-Language Guide](https://bloodsight.com/learn/blood-test-results-explained): How to read blood test results step by step: the flag column, each panel, which results are read together, how to compare them and what a test can't show.
- [How to Read Your CBC Report](https://bloodsight.com/learn/how-to-read-cbc): A CBC report lists red cells, white cells, hemoglobin, hematocrit, platelets, MCV, MCH, MCHC, and RDW. See how to read each row and compare ranges.
- [Understanding Your Metabolic Panel](https://bloodsight.com/learn/understanding-metabolic-panel): Get CMP results explained: kidney, liver, glucose, electrolytes, and what abnormal values could indicate on a comprehensive metabolic panel report.
- [Reading Your Lipid Panel Results](https://bloodsight.com/learn/reading-lipid-panel): Learn how to read your lipid panel. Understand LDL, HDL, triglycerides, reference ranges, and what your results may mean for heart health.
- [How to Read Your Thyroid Panel](https://bloodsight.com/learn/reading-thyroid-panel): A thyroid panel report lists TSH, free T4, total T4, free T3, and total T3 with units and a reference range. See how each row reads and lab differences.
- [How to Read Your Liver Panel](https://bloodsight.com/learn/reading-liver-panel): A liver panel report shows ALT, AST, ALP, GGT, total and direct bilirubin, albumin, and total protein. See how each row reads and what units to look for.
- [Understanding Your Kidney Panel](https://bloodsight.com/learn/reading-kidney-panel): A kidney panel report lists creatinine, BUN, eGFR, and electrolytes (sodium, potassium, chloride, CO2). See how each row reads with units and ranges.
- [Reading Iron Studies Results](https://bloodsight.com/learn/understanding-iron-studies): An iron studies report shows ferritin, serum iron, TIBC, UIBC, transferrin, and transferrin saturation (TSAT). See how each row reads and what units appear.
- [Reading Your Diabetes Panel Results](https://bloodsight.com/learn/reading-diabetes-panel): A diabetes panel report shows HbA1c (%), fasting glucose (mg/dL), random glucose, and estimated average glucose (eAG). See how each row reads on a report.
- [Understanding Inflammation Marker Results](https://bloodsight.com/learn/reading-inflammation-markers): Inflammation marker rows on a lab report show CRP, hs-CRP, and ESR (sed rate) with units and reference ranges. See how each row reads and what changes mean.
- [How to Read Your Hormone Panel](https://bloodsight.com/learn/reading-hormone-panel): Hormone panel reports list TSH, free T4, free T3, testosterone, estradiol, LH, FSH, prolactin, cortisol, and DHEA-S. See how each row reads with units.
- [What Is a Reference Range?](https://bloodsight.com/learn/what-is-reference-range): A reference range is the span a lab calls normal: the middle 95% of healthy people. How it's set, why it varies by age, sex and lab, and its limits.
- [Understanding Lab Test Units](https://bloodsight.com/learn/understanding-lab-units): Lab report units show how a value was measured: mg/dL for glucose, mmol/L for SI labs, IU/L for enzymes, cells/μL for CBC. See how units affect reading values.
- [What Flagged Values on Your Lab Report Mean](https://bloodsight.com/learn/reading-flagged-values): Got an H or L on your lab results? What each flag means (H, L, N, A, HH, LL), why healthy people get flagged, and when a flag needs a call.
- [How to Track Lab Results Over Time](https://bloodsight.com/learn/tracking-lab-trends): Is that change in your blood test real or noise? How much results vary between tests, how to keep them comparable, and what to record when you track labs.
- [Why Lab Results Differ Between Labs (and How to Compare Them)](https://bloodsight.com/learn/comparing-lab-results): Same blood, different numbers? Why Quest, Labcorp and hospital labs report different results and ranges, which tests compare well, and how to compare them.
- [Reading Cardiac Marker Results](https://bloodsight.com/learn/reading-cardiac-markers): Cardiac marker rows on a lab report show troponin I/T, BNP, NT-proBNP, CK, CK-MB, and myoglobin. See how each row reads and what units to look for.
- [How to Read Tumor Marker Results](https://bloodsight.com/learn/reading-tumor-markers): Tumor marker rows on a lab report show PSA, CEA, CA-125, AFP, CA 19-9, and beta hCG with units and ranges. See how each row reads and how trends are tracked.
- [Reading an Autoimmune Panel](https://bloodsight.com/learn/reading-autoimmune-panel): An autoimmune panel report shows ANA, rheumatoid factor (RF), anti-CCP, and complement C3/C4. See how each row reads alongside ESR or CRP if included.
- [Reading a Coagulation Panel](https://bloodsight.com/learn/reading-coagulation-panel): Coagulation rows on a lab report show PT, INR, aPTT, and D-dimer with units and reference ranges. See how each clotting row reads and lab differences.
- [Reading Your Vitamin Panel](https://bloodsight.com/learn/reading-vitamin-panel): A vitamin panel report shows vitamin D, B12, folate, iron, ferritin, magnesium, and zinc with units and ranges. See how each row reads on a lab report.
- [Reading a Female Hormone Panel](https://bloodsight.com/learn/reading-female-hormone-panel): A female hormone panel report shows estradiol, progesterone, FSH, LH, and prolactin with units and reference ranges. See how each row reads on a report.
- [How to Prepare for a Blood Test](https://bloodsight.com/learn/preparing-for-a-blood-test): Preparing for a blood draw covers hydration, fasting, medication notes, and the time of day for tests like glucose or cortisol. See what changes the results.
- [Fasting Before a Blood Test: Water, Coffee and Timing](https://bloodsight.com/learn/fasting-for-lab-tests): Can you drink water or coffee before a blood test? See which tests need fasting, an 8–12-hour timing example, medication questions and what to do if you ate.
- [Best Time of Day for Blood Work](https://bloodsight.com/learn/best-time-for-blood-work): Some lab values shift across the day: cortisol peaks in the morning, testosterone follows a similar pattern, glucose changes with meals. See how timing matters.
- [How Often to Get Routine Blood Work](https://bloodsight.com/learn/how-often-to-get-blood-tests): Routine blood work commonly includes CBC and CMP rows like WBC, RBC, Hgb, glucose, and creatinine. See typical retest intervals and what affects timing.
- [What Are Critical Lab Values?](https://bloodsight.com/learn/understanding-critical-values): Critical (panic) lab values are results a lab must report to your doctor at once. Typical limits at Labcorp and ARUP, who gets the call and what to do.
- [Blood Test Abbreviations: What the Letters Mean](https://bloodsight.com/learn/abbreviations-on-lab-reports): Decode blood test abbreviations by panel: WBC, Hgb, BUN, ALT, LDL, TSH and HbA1c. See alternate names, a sample report and why K/µL changes the number.
- [SI Units vs Conventional Units](https://bloodsight.com/learn/si-vs-conventional-units): Lab reports use SI units (mmol/L, g/L) or conventional units (mg/dL, mg%). See how the same value reads across unit systems and how to compare across labs.
- [Reading Percentile-Based Reference Ranges](https://bloodsight.com/learn/interpreting-percentile-ranges): Some lab reports use percentile-based reference ranges instead of fixed limits. See how percentiles compare with standard ranges and how to read each format.
- [How Accurate Are Blood Tests? Lab Test Accuracy Explained](https://bloodsight.com/learn/understanding-test-accuracy): Lab test accuracy depends on sensitivity (catching true changes), specificity (avoiding false matches), and margin of error. See how each shapes a value.
- [Basic Metabolic Panel (BMP): 8 Tests and Results Explained](https://bloodsight.com/learn/basic-metabolic-panel-explained): Understand the eight BMP blood tests with reference ranges, a full sample report, high and low results, extra calculated rows and a brief BMP vs CMP comparison.
- [At-Home Blood Test: How It Works vs Lab Testing](https://bloodsight.com/learn/at-home-blood-test-explained): Learn how at-home blood test kits collect finger-prick or venous samples, which lab values they measure, and how results compare with lab testing.
- [How Long Do Blood Test Results Take?](https://bloodsight.com/learn/how-long-do-blood-test-results-take): Typical CBC, CMP, lipid panel, hormone panel, and culture turnaround times, plus report status updates, processing steps, and delays.

## Blog

- [All posts](https://bloodsight.com/blog): Notes on reading lab results over time.
- [The Lp(a) of 220 that explained why a 'healthy' 36-year-old ended up in the ER](https://bloodsight.com/blog/lpa-220-ended-up-in-the-er-at-36): Illustrative composite, not a real patient record. A first-person account of a 'clean' lipid panel three weeks before the ER, an Lp(a) of 220 nobody had thought to test, and three generations of pattern.
- [The B12 of 220, the folate that was 'fine,' and the year between](https://bloodsight.com/blog/b12-220-folate-fine-year-between): Illustrative composite, not a real patient record. A first-person account of a year between a 'normal' B12 of 220 and the test that finally explained the tingling, the fog, and the small dropped things.
- [What a testosterone of 280 actually feels like at 38](https://bloodsight.com/blog/testosterone-280-at-38): Illustrative composite, not a real patient record. A 38-year-old's first-person account of the small things — heavier dumbbells, the 4 PM wall, a slowing beard — that turned out to be a testosterone of 280.
- [90 days, three blood draws, one number: what HbA1c actually showed](https://bloodsight.com/blog/90-days-hba1c-monthly): Illustrative composite, not a real patient record. A 38-year-old's three monthly HbA1c draws — 6.0 to 5.9 to 5.6 — what moved the number, what didn't, and why fasting glucose led the way.
- [When 'normal' ferritin isn't normal: the gap between the lab range and how you feel](https://bloodsight.com/blog/when-normal-ferritin-isnt-normal): Illustrative composite, not a real patient record. Two women with 'normal' ferritin and real symptoms. How lab reference ranges are built, what research thresholds say, and how to start the conversation.
- [What a TSH of 12 actually feels like — before you know it's a thyroid](https://bloodsight.com/blog/what-tsh-12-actually-feels-like): Illustrative composite, not a real patient record. An intimate first-person account of the two years of small things — cold hands, the 2 PM wall, hair on the brush — before the TSH of 12.
- [The two-year brain fog that turned out to be one number](https://bloodsight.com/blog/two-year-brain-fog-vitamin-d): Illustrative composite, not a real patient record. An intimate first-person story of two years of brain fog, four doctors, and a vitamin D test that nobody had thought to add until visit four.
- [How Mark took his LDL from 168 to 99 in five months — without statins](https://bloodsight.com/blog/ldl-168-to-99-five-months): Illustrative composite, not a real patient record. A 41-year-old's quiet five-month story of bringing his LDL from 168 to 99 without medication. What changed, what didn't, what he thinks moved it.
- [What your morning cortisol does before that first coffee](https://bloodsight.com/blog/morning-cortisol-and-coffee): A short story about how cortisol moves in the morning, why timing your draw matters, and what changes when caffeine enters the picture.

## Optional

- [About BloodSight](https://bloodsight.com/about): Who builds BloodSight and why.
- [Editorial policy](https://bloodsight.com/editorial-policy): How the reference content is written, sourced, and reviewed.
- [Privacy policy](https://bloodsight.com/privacy): How lab data is stored and handled.
- [Terms of service](https://bloodsight.com/terms): Terms of use.
- [Full context for LLMs](https://bloodsight.com/llms-full.txt): Expanded catalog with reference ranges, causes, and sources.
- [Sitemap](https://bloodsight.com/sitemap.xml): Machine-readable list of every public URL.