Liver Function Panel Updated Apr 17, 2026

Lactate Dehydrogenase (LDH)

Lactate Dehydrogenase (LDH) is an enzyme found in many body tissues and in red blood cells. On a lab report or blood test, LDH helps show how much of this enzyme is present in the sample and how that result compares with the Lactate Dehydrogenase normal range. Because LDH is widely distributed, the LDH test is often read alongside other markers in a Liver Panel to add context to the overall pattern.

What Is Lactate Dehydrogenase (LDH)?

Lactate Dehydrogenase (LDH) is an enzyme measured in blood, not a blood cell count or protein level. It is found in many tissues throughout the body, including muscle, liver, and red blood cells, so LDH on a blood test reflects a broad tissue enzyme signal. On a Lactate Dehydrogenase on a lab report entry, the value shows how much LDH is present in the sample and how it compares with the Lactate Dehydrogenase normal range.

Why Is Lactate Dehydrogenase (LDH) Tested?

LDH is often included in a Liver Panel, and it may also appear in other blood work when a broad tissue-enzyme marker is useful. The LDH test helps add context to the rest of the panel by showing whether the sample has a typical enzyme pattern or a shifted one. In a routine lab report, Lactate Dehydrogenase is usually interpreted with other values rather than by itself. The full name Lactate Dehydrogenase and the abbreviation LDH are both commonly used on reports.

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Lactate Dehydrogenase (LDH) Normal Range

Group Range Unit
Adult Male 140–280 U/L
Adult Female 140–280 U/L

Reference ranges may vary by laboratory and individual factors.

What Does High LDH Mean?

A high LDH result generally means more LDH is present in the blood sample than expected. This can happen when cells release more of the enzyme into the bloodstream, so a high LDH on a lab report often reflects increased cell turnover or tissue breakdown. Values above the Lactate Dehydrogenase reference range, often around 140 to 280 U/L depending on the lab, are typically considered high LDH. The exact LDH test result depends on the method used and the lab’s own reference interval.

Associated factors

Recent hard exercise — muscle activity can temporarily raise LDH in the blood sample.
Sample handling delay — a blood sample that sits too long can let cells release more LDH.
High altitude living — lower oxygen conditions can shift tissue turnover and affect LDH.
Smoking — ongoing exposure can be associated with a higher LDH pattern.
Alcohol intake — regular intake can influence liver-related enzyme patterns, including LDH.
Medications — some medicines can change cell turnover or enzyme release and affect high LDH.
Pregnancy — normal physiologic changes can shift LDH levels in some people.
Recent injury — tissue disruption can release LDH into the bloodstream.
Dehydration — lower plasma volume can concentrate the measured LDH result.
Natural variation — age, sex, and lab method can move results slightly within or near the upper end of normal.

What Does Low LDH Mean?

A low LDH result means less LDH is measured in the sample than expected for that lab. Low LDH is less common than high LDH and often reflects a pattern that is below the Lactate Dehydrogenase normal range rather than a specific blood problem. In many cases, a low LDH test result has limited standalone meaning and is read with the rest of the panel. On a Lactate Dehydrogenase on a blood test, a low value may simply reflect normal biologic variation.

Associated factors

Low muscle mass — less tissue enzyme release can be associated with low LDH.
Low overall protein intake — long-term low intake may reduce tissue enzyme activity patterns.
Vitamin deficiency patterns — low nutrient availability can affect enzyme production and turnover.
Certain medications — some drugs can shift enzyme activity and lead to low LDH.
Overhydration — extra fluid can dilute the measured LDH concentration.
Sample dilution — blood drawn from or near an IV line can lower the apparent LDH.
Laboratory method differences — assay design can report slightly lower values in some settings.
Natural individual variation — some people sit near the lower end of the Lactate Dehydrogenase reference range.
Reduced tissue turnover — slower cell turnover can be associated with low LDH.
Recent rest after exercise — less short-term tissue enzyme release can leave LDH lower than usual.

How Lactate Dehydrogenase (LDH) Relates to Other Values

LDH is often reviewed with alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), and total bilirubin in a Liver Panel. These markers together help show whether the pattern is mainly enzyme-heavy, bilirubin-heavy, or mixed. LDH can also be read with red blood cell count (RBC), hematocrit (Hct), and mean corpuscular volume (MCV) when the broader blood pattern matters. A Lactate Dehydrogenase test result is most useful when viewed with the other numbers on the same report, especially on a Liver Panel.

What Factors Affect Lactate Dehydrogenase (LDH) Levels?

LDH can vary by age, sex, altitude, hydration, and recent physical activity. Time of day and recent food or alcohol intake may also shift a Lactate Dehydrogenase test result slightly. Lab method matters because different instruments can produce different Lactate Dehydrogenase normal range values. In some groups, men and women may have slightly different LDH reference intervals. Ethnicity and local population averages can also influence how a lab sets the range on a blood test.

How It Is Tested

The LDH test is done with a standard blood draw from a vein. The lab measures enzyme activity in the sample and reports the result as a concentration or activity value, usually in U/L. On a Lactate Dehydrogenase on a lab report entry, the number is compared with the lab’s reference interval.

How to Prepare

No fasting is usually required for an LDH test or for Lactate Dehydrogenase as part of a Liver Panel. Recent exercise, alcohol intake, and sample handling can still affect the result.

Frequently Asked Questions

What is a normal LDH level?
A normal LDH level depends on the laboratory, but many adult reference ranges fall around 140 to 280 U/L. The Lactate Dehydrogenase normal range on a lab report should always be checked against the lab’s own interval because methods differ. LDH on a blood test is best read in that local context.
What does LDH stand for?
LDH stands for Lactate Dehydrogenase. It is an enzyme measured in blood and often listed by both the full name and the abbreviation LDH on a lab report. The value is usually compared with the Lactate Dehydrogenase reference range.
What does a high Lactate Dehydrogenase mean on a lab report?
A high Lactate Dehydrogenase result means the measured LDH is above the lab’s expected range. On a lab report, this often reflects increased release of the enzyme from tissues or cells into the blood sample. A high LDH test result is interpreted with the rest of the panel, not alone.
What does a low Lactate Dehydrogenase mean on a lab report?
A low LDH result means the measured Lactate Dehydrogenase is below the lab’s expected range. Low LDH is less common and often has limited meaning by itself. It may reflect natural variation, dilution, or method differences on the blood test.
Can hydration affect Lactate Dehydrogenase?
Yes, hydration can affect the measured LDH concentration. Dehydration can make LDH appear higher by concentrating the blood sample, while overhydration can make it appear lower. This is one reason the Lactate Dehydrogenase test result is read in context.
What is the difference between Lactate Dehydrogenase and ALT?
LDH and ALT are both enzymes, but they reflect different patterns in a blood sample. ALT is more specific to liver cell enzyme release, while LDH is found in many tissues and is broader. On a Liver Panel, the two values are often reviewed together for pattern recognition.
What unit is Lactate Dehydrogenase measured in?
LDH is usually measured in U/L, which means units per liter. Some labs may use slightly different reporting formats, but U/L is the most common unit on a blood test. The unit appears next to the Lactate Dehydrogenase test result on the lab report.
How much can Lactate Dehydrogenase change between tests?
LDH can shift modestly between tests because of normal biologic variation, hydration, exercise, and lab method differences. Small changes near the Lactate Dehydrogenase normal range may not mean much on their own. Bigger jumps are more noticeable when comparing the same lab and similar testing conditions.
Is Lactate Dehydrogenase different for men and women?
Some labs use slightly different LDH reference intervals for men and women, while others use the same range. Sex-related differences are usually small and depend on the lab’s method and local population data. The lab report should list the applicable Lactate Dehydrogenase reference range.
Why is Lactate Dehydrogenase tested in a Liver Panel?
LDH is included in a Liver Panel to add a broad enzyme signal alongside the more liver-focused markers. It helps describe the overall blood pattern when reviewed with ALT, AST, ALP, and bilirubin. The LDH test gives extra context to the panel without pointing to one single source.
What does LDH mean on a blood test?
LDH on a blood test means Lactate Dehydrogenase, an enzyme measured in the sample. The number is compared with the lab’s normal range to show whether the result is within expected limits. On a lab report, LDH is often read with other markers for context.

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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