Lactate (CSF)

CSF Lactate is useful for investigating possible disorders of mitochondrial metabolims, when used in conjenction with cerebrospinal fluid pyruvate collected at the same time to determine the Lactate:Pyruvate ratio. The CSF Lactate:Pyruvate ratio is considered a helpful (not diagnostic) tool in the evaluation of patients with possible disorders of mitochondrial metabolism, especially in patients with neurolofic dysfunction and normal blood Lactate:Pyruvate ratios. Pyruvic acid levels alone have little clinical utility. The Lactate:Pyruvate ratio is elevated in several, but not all, mitochondrial disorders vary widely in presentation and age of onset. Many mitochondral disorders have neurologic and myopathic features and may involve multiple organ systems. Determination of lactate, pyruvate, and L:P ratio in cerebrospinal fluid is helpful in directing attention toward a possible mitochondrial disorder in cases with predominately neurologic dysfunction and normal blood lactate levels. An elevated Lactate:Pyruvate ratio may indicate inherited disorders of the respiratory chain complex, tricarboxylic acide cycle disorders and pyruvate carboxylase deficiency. Respiratory chain defects usually result in Lactate:Pyruvate ratios >20. A low Lactate:Pyruvate raio (disproportionately elevated pyruvic acid) may indicate an inherited disorder of pyruvate metabolism. Defects of the pyruvate dehydrogenase complex result in Lactate:Pyruvate ratios <10. The Lactate:Pyruvate ratio is characteristically normal in other patients. An artifactually high ratio can be found in acutely ill patients.