What is lactate dehydrogenase (LDH)?
LDH is a ubiquitous cellular enzyme released into circulation when cells across many tissues are damaged. It is a non-specific marker of cellular turnover.
Full answer
Lactate dehydrogenase (LDH) is present in virtually every cell type and is released when those cells are injured. Because so many tissues contribute, LDH is highly sensitive but very non-specific. Common causes of elevation include hemolysis (including in vitro hemolysis during sample handling), muscle injury, intense exercise, hepatitis, malignancy, and infarction. Isoenzyme fractionation can localize the source but is rarely used in wellness review. Within oMeds review, isolated mild LDH elevation in an otherwise asymptomatic patient is usually rechecked rather than worked up immediately. Sustained or marked elevation triggers targeted evaluation.
Educational. Not a substitute for individualized provider review.
- LDH — Primary source · oMeds
- Reviewed by Dr. Laura Purdy, MD, MBA · Clinical Director, oMeds · Last reviewed 2026-05-29