Guide Updated Oct 6, 2026

Blood Test Abbreviations: What the Letters Mean

Blood test abbreviations are the short names beside each result: WBC means white blood cells, Hgb means hemoglobin, and BUN means blood urea nitrogen. CBC and CMP name groups of tests. H and L are flags. The unit beside a number tells you how to read it.

The short version

  • Find the panel first: CBC is blood cells, CMP is blood chemistry, and a lipid panel is cholesterol and triglycerides.
  • Different labels can name the same test: Hgb and Hb both mean hemoglobin; SGPT is another name for ALT.
  • Keep the unit with the result. WBC 6.2 K/µL means 6,200 cells/µL, not 6.2 cells/µL.
  • A test name tells you what was measured. H or L tells you where the result sits against the range on that report.

Start with the letters you are looking at, then read the number, unit and range on the same line. The tables below group common abbreviations by the part of the report where you will usually find them.

This is a guide to the labels, not a list of universal normal values. Your lab prints the range it uses beside each result. An abbreviation on its own cannot tell you whether a result needs treatment.

How do you read an abbreviated result on a lab report?

Read all four parts together: the test name, result, unit and reference range. For example, WBC 6.2 K/µL means the lab counted 6,200 white blood cells in each microliter of blood. The example range below belongs to this fictional report.

Jump to CBC, white cell differential, chemistry, cholesterol, thyroid and HbA1c, clotting and inflammation, units or flags.

A fictional CBC result, decoded

Test Result Unit Example range
WBC 6.2 K/µL 4.5–11.0
WBC names the test
White blood cell count
K/µL scales the number
6.2 × 1,000 = 6,200 cells/µL
Fictional WBC result: 6.2 K/µL = 6,200 cells/µL = 6.2 ×10⁹/L. The range is an example, not a cutoff to apply to another report.

The letters and unit do different jobs. WBC names the test; K/µL scales the count. An H or L in a separate column is a high or low flag, not part of the test name.

What do CBC, BMP and CMP stand for?

CBC, BMP and CMP are panel names. Each panel contains several individual results, so a heading such as CBC is not itself a blood cell count.

Panel Full name What is included
CBC / FBC Complete blood count / full blood count Blood cells, hemoglobin, hematocrit and cell indices.
CBC with diff Complete blood count with differential CBC plus a breakdown of the types of white blood cells.
BMP Basic metabolic panel 8 chemistry tests: glucose, calcium, sodium, potassium, chloride, CO2, BUN and creatinine.
CMP Comprehensive metabolic panel The 8 BMP tests plus albumin, total protein, ALP, ALT, AST and bilirubin: 14 tests in all.
Lipid panel / lipid profile Cholesterol and triglyceride testing Total cholesterol, HDL, LDL and triglycerides; some reports add calculated values.

TSH, HbA1c and ferritin are separate tests, not extra parts of a standard CBC or CMP. If a label is missing, check what was ordered. For a walkthrough of the whole document, see how to read blood test results.

What do the CBC abbreviations WBC, RBC, Hgb and PLT mean?

WBC counts white blood cells, RBC counts red blood cells, Hgb measures hemoglobin, and PLT counts platelets. The other CBC labels describe the red cells or platelets in more detail.

Abbreviation / other label Full name What it measures
WBC / leukocytes White blood cell count Number of white blood cells.
RBC / erythrocytes Red blood cell count Number of red blood cells.
Hgb / Hb Hemoglobin Amount of the oxygen-carrying protein in blood.
Hct / PCV Hematocrit / packed cell volume Share of blood volume made up of red blood cells.
MCV Mean corpuscular volume Average red blood cell size.
MCH Mean corpuscular hemoglobin Average amount of hemoglobin per red blood cell.
MCHC Mean corpuscular hemoglobin concentration Average hemoglobin concentration inside red blood cells.
RDW Red cell distribution width How much red blood cell size varies.
PLT / platelets Platelet count Number of platelets, which help form blood clots.
MPV Mean platelet volume Average platelet size.

Hgb and Hct are related but are not interchangeable: Hgb is usually a concentration, while Hct is often a percentage. RDW-CV and RDW-SD also use different units. Read them with the rest of the CBC, not against a cutoff copied from a different label.

What do NEUT, LYMPH and the differential abbreviations mean?

A differential separates white blood cells into types. NEUT means neutrophils, LYMPH means lymphocytes, MONO means monocytes, EOS means eosinophils, and BASO means basophils. Each type may have both a percentage and an absolute count.

Label White blood cell type / measurement
NEUT Neutrophils
LYMPH Lymphocytes
MONO Monocytes
EOS Eosinophils
BASO Basophils
ANC Absolute neutrophil count: number per volume, not a percentage.
Percent and absolute count are different results. With a fictional WBC of 6.2 K/µL and neutrophils of 50%, the absolute neutrophil count is 3.1 K/µL. Do not compare 50% with an absolute-count range.

What do BUN, Cr, eGFR, ALT and AST mean on a chemistry panel?

BUN and Cr are kidney-related measurements; ALT and AST are enzymes often listed with liver tests. A CMP also contains electrolytes, glucose, calcium and proteins. eGFR is an estimate of kidney filtration that often appears alongside creatinine.

Abbreviation / other label Full name What it measures
GLU / glucose Glucose Blood sugar at the time of the draw.
BUN Blood urea nitrogen Nitrogen in urea, a waste product.
Cr / CREA / creatinine Creatinine A waste product used to assess kidney filtration.
eGFR Estimated glomerular filtration rate Calculated estimate of how well the kidneys filter blood.
Na Sodium An electrolyte.
K Potassium An electrolyte.
Cl Chloride An electrolyte.
CO2 / total CO2 Carbon dioxide Mostly bicarbonate in a routine chemistry panel.
Ca Calcium Calcium in blood.
ALB Albumin A protein made by the liver.
TP Total protein Albumin plus other blood proteins.
ALT / SGPT Alanine aminotransferase An enzyme found mainly in the liver.
AST / SGOT Aspartate aminotransferase An enzyme found in the liver and other tissues.
ALP Alkaline phosphatase An enzyme found in the liver, bones and other tissues.
TBIL / total bilirubin Total bilirubin A substance produced when red blood cells break down.

eGFR is commonly reported in mL/min/1.73 m², rather than the mg/dL or µmol/L used for creatinine. A total CO2 result on a CMP is also different from pCO2 on a blood gas report. Use the metabolic panel guide to read these results together.

What do TC, HDL, LDL and TG mean on a lipid panel?

TC is total cholesterol, HDL and LDL name cholesterol-carrying lipoproteins, and TG means triglycerides. On a lipid report, HDL-C and LDL-C specify the cholesterol carried by those particles.

Abbreviation / other label Full name What the report is showing
TC / CHOL Total cholesterol Total cholesterol in blood.
HDL / HDL-C High-density lipoprotein cholesterol Cholesterol carried by HDL particles.
LDL / LDL-C Low-density lipoprotein cholesterol Cholesterol carried by LDL particles; may be calculated or measured.
TG / TRIG Triglycerides A type of fat in blood.
Non-HDL-C Non-HDL cholesterol Total cholesterol minus HDL cholesterol.

Calculated LDL and direct LDL use different methods. If the report says LDL calc, that label describes how the result was obtained. The lipid panel guide explains the parts of the panel.

What do TSH, FT4, FT3 and HbA1c stand for?

TSH, FT4 and FT3 are thyroid-related tests. HbA1c is a blood sugar test that reflects roughly the past 2 to 3 months. HbA1c is different from Hgb on a CBC, even though both names contain hemoglobin.

Abbreviation / other label Full name What it measures
TSH Thyroid-stimulating hormone The pituitary hormone that signals the thyroid.
FT4 / free T4 Free thyroxine T4 that is not bound to blood proteins.
FT3 / free T3 Free triiodothyronine T3 that is not bound to blood proteins.
T4 / total T4; T3 / total T3 Total thyroxine; total triiodothyronine Bound and free hormone together.
HbA1c / A1c Hemoglobin A1c Share of hemoglobin with glucose attached; often reported as % or mmol/mol.

Free T4 and total T4 are different measurements, so they cannot share a reference range. Follow the thyroid panel guide for those labels, or the diabetes panel guide for HbA1c and glucose.

What do CRP, ESR, PT, INR and aPTT mean?

These labels belong to different kinds of testing: CRP and ESR are inflammation markers, while PT, INR and aPTT relate to blood clotting. They are not standard parts of a CBC or CMP.

Abbreviation Full name What it measures
CRP C-reactive protein A protein that can rise with inflammation.
ESR / sed rate Erythrocyte sedimentation rate How quickly red blood cells settle in a test tube.
PT Prothrombin time Time for blood to clot in one lab test.
INR International normalized ratio A standardized calculation based on PT.
aPTT / PTT Activated partial thromboplastin time / partial thromboplastin time Time for blood to clot in a different lab test.

PT and aPTT are usually reported in seconds; INR is a ratio. The target INR for someone taking warfarin is different from the usual reference range for someone who is not. The coagulation guide explains the labels without treating them as interchangeable.

What do K/µL, M/µL, mg/dL and U/L mean?

These are units, not test names. In a count unit, K means thousand and M means million. In the test-name column, K means potassium. The column tells you which meaning applies.

Unit Meaning Example
K/µL / ×10³/µL / ×10⁹/L Thousands of cells per microliter; equivalent count scales. WBC 6.2 K/µL = 6,200 cells/µL = 6.2 ×10⁹/L.
M/µL / ×10⁶/µL / ×10¹²/L Millions of cells per microliter; equivalent count scales. RBC 4.8 M/µL = 4,800,000 cells/µL = 4.8 ×10¹²/L.
mg/dL / g/dL Milligrams / grams per deciliter. BUN often uses mg/dL; hemoglobin often uses g/dL.
mmol/L / µmol/L Millimoles / micromoles per liter. Glucose may use mmol/L; creatinine may use µmol/L.
U/L / IU/L Units / international units per liter. Often used for enzyme activity.
% Percent. Hct and many differential results are percentages.

The symbols µL and uL are two ways of writing microliter. Converting mg/dL to mmol/L needs a different factor for each substance. The lab units guide covers this in more detail.

What do H, L, N, A and RefIntvl mean?

H and L are comparison flags, while RefIntvl is a label for the reference interval. None of them names a biomarker. Use the report’s legend when a lab uses another symbol.

Label Meaning Where it belongs
H / L High / low relative to the lab’s range. Flag column.
N Normal relative to the lab’s range. Flag column; many labs leave it blank instead.
A Abnormal, often for a non-numeric result. Flag column.
HH / LL / AA Critically high / critically low / critically abnormal. Alert flag; check the lab’s legend and contact the ordering clinician promptly.
RefIntvl / Ref Range Reference interval / reference range. The comparison range printed beside the result.

A flag does not explain the cause of a result. Use the flagged values guide for ordinary flags and the critical values guide for urgent alerts.

Questions to bring with your report

  • Does this lab use another name for the same test on my older report?
  • Is this white blood cell result a percentage or an absolute count?
  • Is this LDL result calculated or directly measured?
  • Was the thyroid result free T4 or total T4?
  • Which related results should I read alongside the flagged value?
WBC, Hgb, BUN?

The letters on your report, in plain words.

Upload your report. Each result gets its full test name and a plain-language explanation, with the unit and your lab's own reference range beside it.

Works with Quest, Labcorp, MyChart & PDFs

Example report · labels explained

WBC

White blood cell count

6.2 K/µL

Example lab range: 4.5–11.0

Hgb

Hemoglobin

14.2 g/dL

Example lab range: 12.0–16.0

BUN

Blood urea nitrogen

14 mg/dL

Example lab range: 7–20

Fictional values. Your report keeps its own ranges.

Quick answers about blood test abbreviations

What does WBC mean on a blood test?
WBC means white blood cell count. It counts all white blood cells together. A CBC with differential also lists the types of white blood cells separately, as percentages, absolute counts or both.
Are Hb, Hgb and HbA1c the same test?
Hb and Hgb both mean hemoglobin, the oxygen-carrying protein measured on a CBC. HbA1c measures the share of hemoglobin with glucose attached and reflects roughly the past 2 to 3 months of blood sugar. HbA1c is a separate test.
What do SGOT and SGPT mean?
SGOT is another name for AST, aspartate aminotransferase. SGPT is another name for ALT, alanine aminotransferase. Older reports may use SGOT or SGPT where newer reports use AST or ALT.
What is the difference between CBC and CMP?
CBC means complete blood count and covers blood cells. CMP means comprehensive metabolic panel and contains 14 chemistry tests, including glucose, electrolytes, kidney-related measurements, proteins and liver-related measurements. A CMP does not include a CBC.
What does K mean on a blood test?
In the test-name column, K means potassium. In a cell-count unit such as K/µL, K means thousand. WBC 6.2 K/µL therefore means 6,200 white blood cells per microliter.
What does ABS mean next to neutrophils or lymphocytes?
ABS means absolute count: the number of those cells per volume of blood. A percentage describes their share of the total white blood cells instead. Compare each result with the range printed for that measurement.
Are free T4 and total T4 the same?
No. Free T4 measures thyroxine that is not bound to blood proteins. Total T4 includes both bound and free thyroxine. The two tests use different ranges, so check which one was measured before comparing reports.
Does an H or L tell me what disease I have?
No. H means the result is above the lab’s reference range and L means it is below. The flag does not give a cause or diagnosis. Interpretation also needs the other results, symptoms, medicines and medical history.

Sources

Written by BloodSight Editorial Team · Last updated

Disclaimer

This content is for informational and educational purposes only. It is not intended as medical advice, diagnosis, or treatment recommendation. Reference ranges may vary by laboratory. Always discuss your results with a qualified healthcare professional.

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