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Lactate dehydrogenase (LDH)
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This is the date the draft was written, not a medical review date.
A ubiquitous cytoplasmic enzyme that interconverts lactate and pyruvate. A raised value is a sensitive but non-specific marker of tissue damage or cell turnover.
Reference interval
| Conventional (U/L) | SI (U/L) | |
|---|---|---|
| Adults | 125–220 U/L | 125–220 U/L |
Specimen: Serum or heparinised plasma (non-haemolysed) · Conventional × 1 = SI
Causes of high values
Haemolysis and haemolytic anaemia, megaloblastic anaemia, myocardial or pulmonary infarction, liver disease, muscle injury, lymphoma and other malignancies (including tumour burden in germ-cell tumours), tissue hypoxia, pulmonary embolism, Pneumocystis pneumonia.
Causes of low values
Low values are rare and generally not significant; they may occur with very high vitamin C intake or hereditary subunit deficiency.
Pre-analytical and method notes
Haemolysis in vitro, delayed separation of serum and platelet-rich samples falsely raise LDH; do not refrigerate whole blood. Isoenzyme patterns (LDH-1 to LDH-5) can suggest the tissue of origin but are rarely used now. Reference intervals vary by laboratory, method and population; use the interval printed on the report.
References
- Rifai N, Horvath AR, Wittwer CT. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Elsevier, 6th edition (2018) — Tier 3 (textbook)
- McPherson RA, Pincus MR. Henry's Clinical Diagnosis and Management by Laboratory Methods. Elsevier — Tier 3 (textbook)
- Loscalzo J, et al.. Harrison's Principles of Internal Medicine. McGraw-Hill, 21st edition (2022) — Tier 3 (textbook)
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