The lactate toÂ pyruvate ratio is one tool that clinicians can use to help determine the availability of reducing equivalents in the cell cytosol. It can be useful in distinguishing Pyruvate Dehydrogenase Deficiency from other forms of lactic acidosis, for example. Â Lactate is usually reported inÂ mmol/L and pyruvate is usually reported in mg/dL, thus requiring a unit conversion for pyruvate. This can be accomplished by multiplying pyruvate in mg/dL by a conversion factor of 0.1136 which will give pyruvate in mmol/L. Elevated L/P ratiosÂ can be seen in PDH deficiency, and a paper by Debray et al in Clinical Chemistry (2007) 53 (5): 916-921 entitled “Diagnostic Accuracy of Blood Lactate-to Pyruvate Molar Ratio in the Differential Diagnosis of Congenital Lactic Acidosis” provides some useful guidelines for determining if a ratio is elevated above normal.
Hilary Vernon, MD PhD