Lactate
Overview
Lactate measures the concentration of lactic acid (lactate anion) in blood, the end product of anaerobic glycolysis when oxygen demand exceeds supply. It serves as a marker of tissue perfusion, metabolic stress, and oxygen debt during critical illness. Elevated levels indicate conditions like sepsis, shock, heart failure, or severe exercise, while very low levels are uncommon but may occur in liver failure or regional hypoperfusion. Clinically, lactate testing guides resuscitation efforts, risk stratification, and prognosis in acute care settings.
Clinical Use Cases
- Assessing severity and monitoring treatment response in sepsis and septic shock.
- Evaluating tissue hypoperfusion in shock states (cardiogenic, hypovolemic, distributive).
- Guiding resuscitation protocols in emergency and critical care medicine.
- Risk stratification in cardiac arrest and post-arrest care.
Specimen Types
- Whole blood (arterial preferred; venous acceptable).
- Plasma.
Measurement Methods
- Blood gas analyzer (enzymatic amperometric electrode).
- Point-of-care lactate meters.
- Laboratory colorimetric enzymatic assay.
Test Preparation and Influencing Factors
- No fasting required; collect during clinical evaluation.
- Prolonged venous tourniquet, hemolysis, or delayed processing falsely elevate lactate.
- Recent seizure, epinephrine, or high-dose beta-agonists increase lactate.
- Liver dysfunction impairs lactate clearance independent of production.
Synonyms
- Lactic acid.
- Blood lactate.