Health information to help you understand symptoms. It isn't a diagnosis.
Check symptoms

LDH test

Also called: Lactate dehydrogenase

LDH is an enzyme released when cells are damaged. A high level shows tissue damage but not where.

SampleA small tube of blood from a vein in your arm
Fasting?Usually not needed
ResultsUsually within 1 to 2 days
Good to knowOne result rarely tells the whole story. Your provider looks at your results together with your symptoms, exam, and other tests.

What the test is

It's used to follow some blood cancers and red cell breakdown.

Why it's done

  • Possible red cell breakdown (hemolysis)
  • Following lymphoma or other cancers
  • Tissue damage

Getting ready and what happens

  • No preparation is needed.

How the test is done

  • A health worker cleans the skin, puts a band around your arm, and draws blood from a vein with a small needle. It takes a few minutes.

What the results mean

ResultTypical range for adults
LDHAbout 140 to 280 U/L (labs vary)

Normal ranges vary from lab to lab and can differ by age, sex, and pregnancy. Your report lists your lab's own range next to each result. A result a little outside the range is often not a problem.

High

Can come from hemolysis, liver or muscle damage, infections, or some cancers.

Questions to ask your provider

  • What do my results mean for me?
  • Do I need to repeat this test or have other tests?

Risks

A blood draw is very safe. You may have slight pain or a small bruise where the needle went in.

Related conditions

Related tests

Sources

Last updated 2026-11-13.