Lactate dehydrogenase test

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Lactate dehydrogenase (LDH) is a protein that helps produce energy in the body. An LDH test measures the amount of LDH in the blood.

Alternative Names

LDH test; Lactic acid dehydrogenase test

How the Test is Performed

A blood sample is needed.

How to Prepare for the Test

Your health care provider may ask you to stop taking certain medicines that may affect your test results. Medicines that can increase LDH measurements include numbing medicines (anesthetics), aspirin, clofibrate, fluorides, mithramycin, opioids, and procainamide. If you take any of these, tell your provider before your test.

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.

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:

  • Low red blood cell count (anemia)
  • Cancer, including blood cancer (leukemia) or lymph cancer (lymphoma)

Normal Results

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.

What Abnormal Results Mean

A higher-than-normal level may indicate:

If your LDH level is high, your provider may recommend an LDH isoenzymes test to determine the location of any tissue damage.


Veins and arteries vary in size from one person to another and from one side of the body to the other. Obtaining a blood sample 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
  • Hematoma (blood buildup under the skin)
  • Infection (a slight risk any time the skin is broken)


Chernecky CC, Berger BJ. L. In: Chernecky CC, Berger BJ, eds. Laboratory Tests and Diagnostic Procedures. 6th ed. St. Louis, MO: Elsevier Saunders; 2013: chap L.

Ferri FF. Laboratory tests and interpretation of results. In: Ferri FF, ed. Ferri's Clinical Advisor 2014. Philadelphia: PA: Elsevier Mosby; 2014: Section IV.

Version Info

  • Last reviewed on 1/31/2016
  • Laura J. Martin, MD, MPH, ABIM Board Certified in Internal Medicine and Hospice and Palliative Medicine, Atlanta, GA. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.

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