Source-checked
Blood gases
Lactate
Source-checked · Content last updated · 1 min read ·
This is the date the draft was written, not a medical review date.
The end product of anaerobic glycolysis, cleared mainly by the liver. A level above 2 mmol/L is hyperlactataemia, and a persistently raised value is a marker of tissue hypoperfusion and a prognostic indicator in critical illness.
Reference interval
| Conventional (mg/dL) | SI (mmol/L) | |
|---|---|---|
| Adults | 4.5–18 mg/dL | 0.5–2 mmol/L |
Specimen: Arterial or venous whole blood (heparin or fluoride), on ice · Conventional × 0.111 = SI
Causes of high values
Type A: shock (septic, cardiogenic, hypovolaemic), severe hypoxaemia, cardiac arrest, mesenteric ischaemia, seizures. Type B: liver failure, metformin toxicity, thiamine deficiency, malignancy, adrenaline infusion, beta-agonists, inborn errors of metabolism.
Causes of low values
Low values are not clinically significant.
Pre-analytical and method notes
Normal is below 2 mmol/L (about 18 mg/dL). Prolonged tourniquet use, fist clenching and delay before analysis falsely raise lactate; the sample should be placed on ice and analysed promptly. Venous values usually approximate arterial values when perfusion is adequate. Reference intervals vary by laboratory, method and population; use the interval printed on the report.
Related calculators
References
- Loscalzo J, et al.. Harrison's Principles of Internal Medicine. McGraw-Hill, 21st edition (2022) — Tier 3 (textbook)
- Rifai N, Horvath AR, Wittwer CT. Tietz Textbook of Clinical Chemistry and Molecular Diagnostics. Elsevier, 6th edition (2018) — Tier 3 (textbook)
- Hall JE, Hall ME. Guyton and Hall Textbook of Medical Physiology. Elsevier, 14th edition (2020) — Tier 3 (textbook)
References are listed only where the article cites them. See the sources page for the full policy. How sources are chosen and credited