Lactate is one of the substances produced by cells as the body during anaerobic (oxygen deficient) energy production. It is produced by muscle cells, red blood cells, brain, and other tissues. This test can be ordered when a patient shows symptoms of hypoxia or suspects shock, heart attack, severe congestive heart failure, renal failure, uncontrolled diabetes and as part of an initial evaluation of someone who is suspected of having sepsis. Plasma collected in sodium fluoride or potassium oxalate are recommended specimens