American Association of Critical-Care Nurses (AACN) Certification Practice Test

At what level of lactate is lactic acidosis identified?

1. Less than 2 mmol/L

2. 2-4 mmol/L

3. 4-6 mmol/L

4. More than 4 mmol/L

The correct answer is: More than 4 mmol/L

Lactic acidosis is typically identified when lactate levels exceed 4 mmol/L. This threshold is clinically significant because it indicates a state where the body is producing lactate at a rate that overwhelms its clearance, often due to tissue hypoxia or metabolic disturbances. The lactic acid accumulation leads to a decrease in blood pH, resulting in acidosis, which can have severe physiological consequences if not addressed. In normal physiological conditions, lactate levels are generally under 2 mmol/L. Levels between 2-4 mmol/L may indicate a mild elevation, but this does not necessarily signify lactic acidosis. It's the levels above 4 mmol/L that are critical, as they suggest a higher likelihood of metabolic distress and require immediate evaluation and intervention to prevent complications, such as organ dysfunction or failure. Thus, identifying lactic acidosis at this lactate concentration is essential for timely and effective clinical management.