Clinical Significance

Lactate is a byproduct of glucose metabolism.  The intermediary step in this pathway in the conversion of pyruvate to lactate by lactate dehydrogenase.  Lactate is generated in red blood cells, muscle, the brain and the gut.  Under normal circumstances, there is a small amount of lactate in the blood.  Type A lactic acidosis is caused by insufficient oxygenation of tissues.  In the decreased oxygen environment, anaerobic metabolism results.  Causes include circulatory failure, trauma, and profound anemia most commonly associated with strenuous exertion and exercise.  Type B lactic acidosis is due to overproduction of lactate or inadequate oxygen utilization most commonly associated with malignancies, diabetes, severe infection and several drugs.