The lactate dehydrogenase (LDH) test measures the amount of LDH in the blood.

See also: LDH isoenzymes

The health care provider will take blood from a vein or from your heel, finger, toe, or earlobe.

The blood sample is sent to a laboratory, where it is placed in a machine called a centrifuge. The machine quickly spins the blood, which causes the liquid part (the serum) to separate from the cells. The LDH measurement is done on the serum.

Your health care provider may ask you to stop taking drugs that may affect the test. Drugs that can increase LDH measurements include anesthetics, aspirin, clofibrate, fluorides, mithramycin, narcotics, and procainamide.

LDH is most often measured to check for tissue damage. The enzyme LDH is in many body tissues, especially the heart, liver, kidney, skeletal muscle, brain, blood cells, and lungs.

Other conditions under which the test may be done:

• Anemia of vitamin B-12 deficiency
• Megaloblastic anemia
• Pernicious anemia

A typical range is 105 - 333 IU/L (international units per liter).

Normal value ranges may vary slightly among different laboratories. Talk to your doctor about the meaning of your specific test results.

Higher-than-normal levels may indicate:

• Blood flow deficiency (ischemia)
• Cerebrovascular accident (such as a stroke)
• Heart attack
• Hemolytic anemia
• Infectious mononucleosis
• Liver disease (for example, hepatitis)
• Low blood pressure
• Muscle injury
• Muscular dystrophy
• New abnormal tissue formation (usually cancer)
• Pancreatitis
• Tissue death

If the LDH level is raised, your doctor may order an LDH isoenzymes test.

Abraham N, Carty R, DuFour D, Pincus M. Clinical enzymology. In: McPherson R, Pincus M, eds. Henry’s Clinical Diagnosis and Management by Laboratory Methods. 21st ed. Philadelphia, Pa: Saunders Elsevier; 2006:chap 20.

Schwartz R. Autoimmune and intravascular hemolytic anemias. In: Goldman L, Ausiello D, eds. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 164.