Lactate Dehydrogenase (LDH)
Measures tissue damage from various conditions.
Content last reviewed 2026-09-12 · Educational information — not medical advice
It is commonly considered when evaluating Sepsis, Lymphoma, Dehydration; people with Fatigue, Fever, Hypotension may have it ordered as part of their work-up.
What is the Lactate Dehydrogenase (LDH)?
The Lactate Dehydrogenase (LDH) is a laboratory blood test that measures lactate dehydrogenase (LDH), an enzyme released when tissue is damaged anywhere in the body.
How the Lactate Dehydrogenase (LDH) works
Standard venous blood sampling analyzed with clinical-laboratory instrumentation appropriate to the measurand.
Why healthcare providers order it
Ordered within broader clinical workups when a provider wants this specific measurand quantified.
Interpreting your results
Understanding your result
Compare your value against the reference interval printed on your report — laboratories publish their own instrument- and population-derived ranges. Values outside the range are flags for clinical interpretation, not verdicts; borderline results are frequently reconfirmed before acting.
What your LDH result means
If high: LDH is non-specific — it rises with hemolysis, liver disease, malignancy, and tissue injury, and is interpreted alongside other markers.
Reference intervals vary by laboratory, instrument, age, sex, and — for hormones — collection time. Always compare your value against the range printed on your own report, and review results with a qualified healthcare professional who knows your history. This guide is educational and does not diagnose.
Understanding your lab report
- Find the reference interval printed beside your value on the report — that pairing defines 'normal' for this lab run.
- Note the units. mmol/L vs mg/dL, ng/mL vs µg/L — numbers mean nothing across unit systems.
- Look at flags (H/L) but read the degree: barely-outside values behave differently than multiples of the limit.
- Trends outrank snapshots. A series of results tells your provider far more than any single draw.
Conditions that may involve Lactate Dehydrogenase (LDH)
Symptoms that may lead to this test
Frequently asked questions
What does the Lactate Dehydrogenase (LDH) measure?
It measures lactate dehydrogenase (LDH), an enzyme released when tissue is damaged anywhere in the body.
What does a high LDH result mean?
LDH is non-specific — it rises with hemolysis, liver disease, malignancy, and tissue injury, and is interpreted alongside other markers.
Do I need to fast before the Lactate Dehydrogenase (LDH)?
Fasting is not routinely required for this test; follow any instructions from your provider or laboratory.
How soon do Lactate Dehydrogenase (LDH) results come back?
Most routine assays return within 1–3 business days; specialty methods can extend that to a week or more.
Can an abnormal Lactate Dehydrogenase (LDH) result mean something serious?
Abnormal results range from benign to urgent; degree, direction, and trend — reviewed by a clinician who knows your history — determine what happens next.
Sources & data provenance
- Family-specific guidance compiled from standard clinical laboratory medicine references