Label Mnemonic: PYRCF
Epic code: LAB3942
Downtime form: A-1a Doctor/Provider Orders - Pathology Core and Specialty Care Nursery
Commercial Mail-out Laboratory
5231 RCP
Collection Medium:
CSF collection kit
Preferred Minimum: 0.6 mL CSF from CSF tube #2
Absolute Minimum: 0.3 mL CSF from CSF tube #2
Turn Around Time:
6-8 days upon receipt at reference laboratory
Reference Range:
0.06-0.19 mmol/L
Interpretive Data:
An elevated lactate-to-pyruvate (L:P) ratio may indicate inherited disorders of the respiratory chain complex, tricarboxylic acid cycle disorders and pyruvate carboxylase deficiency. Respiratory chain defects usually result in L:P ratios >20.

A low L:P ratio (disproportionately elevated pyruvic acid) may indicate an inherited disorder of pyruvate metabolism. Defects of the pyruvate dehydrogenase complex result in L:P ratios <10.

The L:P ratio is characteristically normal in other patients. An artifactually high ratio can be found if the patient is acutely ill.
Correct specimen collection and handling is crucial to achieve reliable results.

Pyruvic acid levels alone have little clinical utility. Abnormal concentrations of pyruvic acid, and lactate-to-pyruvate (L:P) ratios, are not diagnostic for a particular disorder but must be interpreted in the context of the patient's clinical presentation and other laboratory studies.

For the L:P ratio, both analytes should be determined on the same specimen.

When comparing blood and cerebrospinal fluid (CSF) L:P ratios, blood and CSF specimens should be collected at the same time.
Test Limitations:
The CSF L:P ratio is considered a helpful (not diagnostic) tool in the evaluation of patients with possible disorders of mitochondrial metabolism, especially in patients with neurologic dysfunction and normal blood L:P ratios. Pyruvic acid levels alone have little clinical utility.
Spectrophotometry (SP)
CPT Code:
See also:
Pyruvic Acid, Blood