Which metabolic acidosis is characterized by an increased lactic acid concentration?

Lactic acidosis is specifically characterized by an accumulation of lactic acid in the body, which leads to metabolic acidosis. This condition can arise from various factors such as increased production of lactic acid due to hypoxia, sepsis, or any condition causing impaired oxygen utilization by cells. The elevated levels of lactic acid decrease the blood pH, resulting in the metabolic acidosis that is hallmark to this condition.

In contrast, hyperchloremic acidosis is generally caused by an increase in chloride levels, which does not involve lactic acid. Metabolic acidosis from diabetic ketoacidosis is caused primarily by the accumulation of ketone bodies, not lactic acid. Renal tubular acidosis results from a failure of the kidneys to properly acidify urine or reabsorb bicarbonate, which can lead to metabolic acidosis, but it is also not due to lactic acid accumulation. Therefore, the unique feature of lactic acidosis—its direct association with elevated lactic acid levels—distinguishes it as the correct answer in this context.