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Lactate Dehydrogenase (LDH) Test

What is a lactate dehydrogenase (LDH) test?

This test measures the level of lactate dehydrogenase (LDH), also known as lactic acid, in your blood or sometimes in other body fluids. LDH is a type of protein, known as an enzyme. LDH plays an important role in making your body's energy. It is found in almost all the body's tissues, including those in the blood, heart, kidneys, brain, and lungs.

When these tissues are damaged, they release LDH into the bloodstream or other body fluids. If your LDH blood or fluid levels are high, it may mean certain tissues in your body have been damaged by disease or injury.

Other names: LD test, lactic dehydrogenase, lactic acid dehydrogenase

What is it used for?

An LDH test is most often used to:

Why do I need an LDH test?

You may need this test if other tests and/or your symptoms indicate you have tissue damage or disease. Symptoms will vary depending on the type of tissue damage you have.

You may also need an LDH test if you are currently being treated for cancer.

What happens during an LDH test?

A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

LDH is sometimes measured in other body fluids, including fluids in the spinal cord, lungs, or abdomen. If you are having one of these tests, your health care provider will give more information about the procedure.

Will I need to do anything to prepare for the test?

You don't need any special preparations for an LDH blood test.

Are there any risks to the test?

There is very little risk to having a blood test. You may have slight pain or bruising at the spot where the needle was put in, but most symptoms go away quickly.

What do the results mean?

Higher than normal LDH levels usually means you have some type of tissue damage or disease. Disorders that cause high LDH levels include:

Although the test can show if you have tissue damage or disease, it does not show where the damage is located. If your results showed higher than normal LDH levels, your provider may need to order more tests to make a diagnosis. One of these tests may be an LDH isoenzyme test. An LDH isoenzyme test measures different forms of LDH. It can help your provider find out about the location, type, and severity of tissue damage.

If you have questions about your results, talk to your health care provider.

References

  1. Kids Health from Nemours [Internet]. Jacksonville (FL): The Nemours Foundation; c1995–2019. Blood Test: Lactate Dehydrogenase [cited 2019 Jul 1]; [about 2 screens]. Available from: https://kidshealth.org/en/parents/test-ldh.html
  2. Lab Tests Online [Internet]. Washington D.C.; American Association for Clinical Chemistry; c2001–2019. Cerebrospinal Fluid (CSF) [updated 2017 Nov 30; cited 2019 Jul 1]; [about 3 screens]. Available from: https://labtestsonline.org/glossary/cerebrospinal
  3. Lab Tests Online [Internet]. Washington D.C.; American Association for Clinical Chemistry; c2001–2019. Lactate Dehydrogenase (LD) [updated 2018 Dec 20; cited 2019 Jul 1]; [about 2 screens]. Available from: https://labtestsonline.org/tests/lactate-dehydrogenase-ld
  4. Lab Tests Online [Internet]. Washington D.C.; American Association for Clinical Chemistry; c2001–2019. Meningitis and Encephalitis [updated 2018 Feb 2; cited 2019 Jul 1]; [about 3 screens]. Available from: https://labtestsonline.org/conditions/meningitis-and-encephalitis
  5. Lab Tests Online [Internet]. Washington D.C.; American Association for Clinical Chemistry; c2001–2019. Peritoneal Fluid Analysis [updated 2019 May 13; cited 2019 Jul 1]; [about 3 screens]. Available from: https://labtestsonline.org/tests/peritoneal-fluid-analysis
  6. Lab Tests Online [Internet]. Washington D.C.; American Association for Clinical Chemistry; c2001–2019. Pleural Fluid Analysis [updated 2019 May 13; cited 2019 Jul 1]; [about 3 screens]. Available from: https://labtestsonline.org/tests/pleural-fluid-analysis
  7. National Cancer Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; NCI Dictionary of Cancer Terms: tissue [cited 2019 Jul 1]; [about 3 screens]. Available from: https://www.cancer.gov/publications/dictionaries/cancer-terms/search?contains=false&q=tissue
  8. National Heart, Lung, and Blood Institute [Internet]. Bethesda (MD): U.S. Department of Health and Human Services; Blood Tests [cited 2019 Jul 1]; [about 3 screens]. Available from: https://www.nhlbi.nih.gov/health-topics/blood-tests
  9. University of Rochester Medical Center [Internet]. Rochester (NY): University of Rochester Medical Center; c2019. Health Encyclopedia: Lactic Acid Dehydrogenase (Blood) [cited 2019 Jul 1]; [about 2 screens]. Available from: https://www.urmc.rochester.edu/encyclopedia/content.aspx?contenttypeid=167&contentid=lactic_acid_dehydrogenase_blood
  10. UF Health: University of Florida Health [Internet]. Gainesville (FL): University of Florida Health; c2019. Lactate dehydrogenase test: Overview [updated 2019 Jul 1; cited 2019 Jul 1]; [about 2 screens]. Available from: https://ufhealth.org/lactate-dehydrogenase-test
  11. UW Health [Internet]. Madison (WI): University of Wisconsin Hospitals and Clinics Authority; c2019. Lactic Acid Dehydrogenase (LDH): Exam Overview [updated 2018 Jun 25; cited 2019 Jul 1]; [about 2 screens]. Available from: https://www.uwhealth.org/health/topic/testdetail/lactic-dehydrogenase-ldh/tv6985.html#tv6986

The medical information provided is for informational purposes only, and is not to be used as a substitute for professional medical advice, diagnosis or treatment. Please contact your health care provider with questions you may have regarding medical conditions or the interpretation of test results.

In the event of a medical emergency, call 911 immediately.