Lactate Dehydrogenase (LDH) Test
Reviewed
Also called: LD test, lactic dehydrogenase, lactic acid dehydrogenase
A lactate dehydrogenase (LDH) test usually measures the level of lactate dehydrogenase (LDH) in a sample of your blood.
Specimen: blood (or other body fluids such as cerebrospinal fluid, peritoneal fluid, pleural fluid)
Why this test may be ordered
- To help diagnose or monitor conditions affecting the blood, liver, lungs, kidneys, heart, pancreas, brain, or spinal cord
- To monitor chronic conditions such as muscular dystrophy or HIV
- To help diagnose certain severe infections
- To assess the severity of certain cancers (e.g., multiple myeloma, lymphoma, leukemia, testicular cancer, melanoma)
- To check whether cancer treatment is working
Preparation and collection
You don't need any special preparations for an LDH blood test. If your test uses other fluid samples, your provider will tell you how to prepare.
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.
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. If you are having another type of test, your provider will explain the risks.
Understanding results
The meaning of your LDH test results depends on the reason you had the test, your symptoms, and the results of other tests you've had.
- Higher than normal LDH level: In general, LDH levels that are higher than normal usually mean you have some type of tissue damage. Limitation: High levels can be caused by intense exercise and certain medicines, including aspirin. Next step: Your provider may order more tests to diagnose your condition.
- Lower than normal LDH level: Lower than normal LDH levels aren't common and usually aren't considered to be a health problem. Limitation: Taking large amounts of vitamin C or vitamin E may cause low levels. Next step: So, ask your provider to explain what your results say about your health.
- An LDH test alone cannot show what is damaging your tissues or where the damage is located.
- High levels can be caused by intense exercise, certain medicines, or sample handling issues, not just disease.
- Low levels are uncommon and usually not a health problem.
What to do next
So, ask your provider to explain what your results say about your health.
- Why do I need this test?
- What do my results mean for my health?
- Do I need any follow-up tests?
Evidence source
Source: U.S. National Library of Medicine (MedlinePlus). Practices and reference ranges may differ in your country.
U.S. National Library of Medicine: Lactate Dehydrogenase (LDH) Test