Lactate dehydrogenase (LDH) is a protein that helps produce energy in the body. An LDH test measures the amount of LDH in the blood.
How the Test is Performed
A blood sample is needed.
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others feel only a prick or stinging. Afterward, there may be some throbbing or a slight bruise. This soon goes away.
How to Prepare for the Test
No specific preparation is necessary.
Normal value range is 105 to 333 international units per liter (IU/L).
Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or test different samples. Talk to your provider about the meaning of your specific results.
There is little risk involved with having your blood taken. Veins and arteries vary in size from one person to another and from one side of the body to the other. Taking blood from some people may be more difficult than from others.
Other risks associated with having blood drawn are slight, but may include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Multiple punctures to locate veins
- Hematoma (blood buildup under the skin)
- Infection (a slight risk any time the skin is broken)
What Abnormal Results Mean
A higher-than-normal level may indicate:
- Blood flow deficiency (ischemia)
- Heart attack
- Hemolytic anemia
- Infectious mononucleosis
- Leukemia or lymphoma
- Liver disease (for example, hepatitis)
- Low blood pressure
- Muscle injury
- Muscle weakness and loss of muscle tissue (muscular dystrophy)
- New abnormal tissue formation (usually cancer)
- Tissue death
If your LDH level is high, your provider may recommend an LDH isoenzymes test to determine the location of any tissue damage.
Why the Test is Performed
LDH is most often measured to check for tissue damage. LDH is in many body tissues, especially the heart, liver, kidney, muscles, brain, blood cells, and lungs.
Other conditions for which the test may be done include:
Carty RP, Pincus MR, Sarafraz-Yazdi E. Clinical enzymology. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 23rd ed. St Louis, MO: Elsevier; 2017:chap 20.
Chernecky CC, Berger BJ. Lactate dehydrogenase. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St Louis, MO: Elsevier Saunders; 2013:701-702.