Health Encyclopedia

LDH

Definition

LDH is a blood test that measures the amount of lactate dehydrogenase (LDH).

Alternative Names

Lactate dehydrogenase; Lactic acid dehydrogenase

How the test is performed

The health care provider draws blood from a vein or from a heel, finger, toe, or earlobe. The laboratory quickly spins (centrifuges) the blood to separate the serum (liquid portion) from the cells. The LDH test 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.

LDH affects the chemical reaction for the conversion of pyruvate and lactate. Exercising muscles convert (and red blood cells metabolize) glucose to lactate. Lactate is released into the blood and is later taken up by the liver. The liver converts lactate back to glucose and releases glucose into the blood. Resting muscles, red blood cells, and other tissues then take up this glucose.

Normal Values

Normal values may vary slightly from one lab to another. A typical range is 105 - 333 IU/L (international units per liter).

What abnormal results mean

Higher-than-normal levels may indicate:

Cerebrovascular accident (CVA, stroke)
Heart attack
Hemolytic anemia
Low blood pressure
Infectious mononucleosis
Blood deficiency (intestinal ischemia)
Liver disease (for example, hepatitis)
Muscle injury
Muscular dystrophy
New abnormal tissue formation (neoplastic) states
Pancreatitis
Tissue death (pulmonary infarction)

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

Other conditions under which the test may be done:

References

Abeloff MD, Armitage JO, Niederhuber JE, Kastan MB, McKenna WG. Clinical Oncology. 3rd ed. Philadelphia, Pa: Churchill Livingstone, 2004.

Ferri FF. Ferri's Clinical Advisor 2007. Philadelphia, Pa: Mosby, 2006.

Review Date:3/13/2007
Reviewed By:Mark Levin, M.D., Hematologist and Oncologist, Newark, NJ. Review provided by VeriMed Healthcare Network.

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