What is indicated by a lactate level greater than 4?

A lactate level greater than 4 is indicative of lactic acidosis, which occurs when there is an accumulation of lactic acid in the body due to anaerobic metabolism. This typically signifies that the body is under stress, often from conditions such as severe sepsis, shock, or tissue hypoxia.

In healthy metabolism, lactate levels are maintained within a normal range, usually below 2 mmol/L, under aerobic conditions. A rapid rise in lactate levels suggests that the body's tissues are not receiving sufficient oxygen to meet metabolic demands, leading to anaerobic processes that generate lactate. As lactate levels exceed 4 mmol/L, it indicates a significant metabolic derangement that requires immediate medical attention.

Understanding this context helps to assess the severity of the patient's condition and guide appropriate interventions.