L-lactate and D-lactate - clinical significance of the difference

In all vertebrates, including humans, the L-lactate form is by far the most abundant and pathophysiologically significant, and it is this form that is specifically measured by the lactate sensors in blood gas analyzers and indeed all routine methods used to measure lactate in the clinical laboratory. The main focus of this brief review is physiological and pathological aspects that distinguish L-lactate and D-lactate. Consideration will be given to the very rare instance when measurement of blood D-lactate is clinically useful and just why the lactate sensor in blood gas analyzers is not useful in such rare circumstance.