LDH (Lactate Dehydrogenase): what your level actually means
Also known as: Lactate Dehydrogenase, LD · Updated 19 Aug 2026 · Educational — not medical advice
The short answer: LDH (lactate dehydrogenase) usually falls between about 140 and 280 U/L in adults, though exact lab cutoffs vary. It is an enzyme found in nearly every cell in the body, so a high result signals that cells somewhere — in the heart, liver, muscles, blood, or elsewhere — are being damaged or breaking down faster than usual, without pointing to a specific organ on its own. It is almost always interpreted alongside more specific tests.
Where does your value sit?
This LDH (Lactate Dehydrogenase) value is inside the normal range. Your lab's printed reference range takes precedence — ranges vary slightly between laboratories.
What LDH tells you
LDH is an enzyme that helps cells convert sugar into energy, and because it exists in almost every tissue type, it spills into the blood whenever cells are injured or destroyed, whatever the cause. That makes it one of the least specific but most broadly sensitive markers of tissue damage available on routine blood work. (Illustration is schematic.)
Common reasons it rises
- Hemolysis — the breakdown of red blood cells, whether from a lab handling issue or a true blood disorder, releases large amounts of LDH.
- Liver damage — hepatitis or other liver injury raises LDH alongside liver-specific enzymes like ALT and AST.
- Heart attack or muscle injury — damaged heart or skeletal muscle cells also release LDH, though it rises later and less specifically than troponin or CK.
- Certain cancers — some blood cancers and tumors with rapid cell turnover produce notably high LDH, so it is sometimes used to track disease activity.
- Strenuous exercise or tissue trauma — vigorous exertion or recent injury can transiently raise LDH in otherwise healthy people.
And reasons it runs low
- Low LDH is rarely clinically significant and is not typically linked to a specific disease.
- Genetic LDH deficiency — a rare inherited condition can cause naturally low levels without other health effects.
Does food or exercise change this?
Check with your doctor first: If a high result follows a heart attack, liver problem, or unexplained cause rather than recent intense exercise, follow up with your doctor promptly rather than waiting it out.
General guidance for adults — not a personal diet plan. Your doctor or dietitian knows your full picture.
Checked against: LDH test (MedlinePlus) · Lactate dehydrogenase test (MedlinePlus)
What to do next
Ask your doctor: “Which organ or tissue does this LDH elevation most likely point to in my case?”
Ask your doctor: “Do we need more specific tests, like liver enzymes or troponin, to narrow down the cause?”
Ask your doctor: “Could this result reflect a lab handling issue, like a delayed or mishandled sample?”
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Questions people ask
Why is LDH considered a nonspecific test?
LDH exists inside nearly every type of cell in the body, so almost any process that damages or destroys cells — infection, injury, hemolysis, or cancer — can raise it. That broad sensitivity is useful as a red flag but means LDH alone cannot say which organ or condition is responsible.
Can a blood draw itself falsely raise LDH?
Yes. If red blood cells rupture in the collection tube during or after the draw, a process called hemolysis, LDH can appear falsely elevated even though nothing is wrong inside the body. Labs sometimes recommend a repeat sample if this is suspected.
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