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LDH Isoenzymes

Definition

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

See also: LDH isoenzymes

Alternative Names

LDH test; Lactic acid dehydrogenase test

How the test is performed

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.

How to prepare for the test

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.

Why the test is performed

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

Normal Values

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.

What abnormal results mean

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.

References

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.

Gregg X, Prchal JT. Red Blood Cell Enzymopathies. In: Hoffman R, Benz EJ, Shattil SS, et al, eds. Hematology: Basic Principles and Practice. 5th ed. Philadelphia, Pa: Elsevier Churchill Livingstone; 2008:chap 45.

Review Date: 3/21/2010

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Information developed by A.D.A.M., Inc. regarding tests and test results may not directly correspond with information provided by UCSF Medical Center. Please discuss with your doctor any questions or concerns you may have.