Pyruvic Acid
Label Mnemonic: PYR
Epic Lab Code: LAB3938
Downtime Form: A-1a Miscellaneous Request
Commercial Mail-out Laboratory
5231 RCP
356-8593
Specimen(s):
Blood
Specimen Instructions:
Fasting (at least 4 hours). Once drawn, immediately transfer blood to special collection tube (pre-chilled) and shake vigorously to mix.

Note:
1. Supplied collection tube expires 12 months after preparation. Check expiration date before using.
2. Special collection tube must be pre-chilled prior to draw.
3. If perchloric acid spills, specimen must be redrawn.
Collection Medium:
T012 Pyruvate Tube
Minimum:
Draw enough blood directly into syringe to add exactly 1 mL of blood to the special collection tube (pre-chilled). SHAKE virgorously.

This is a specialized collection tube that contains preservative that keeps pyruvic acid stable until analysis is done. The tube can be obtained from Specimen Control at 356- 3527.
Rejection Criteria:
Samples collected in any tube other than the special T012 tube will be rejected.
Delivery Instructions:
Deliver to laboratory immediately after collection.
Turn Around Time:
6 days upon receipt in reference laboratory (not reported on Saturday and Sunday)
Reference Range:
0.08-0.16 mmol/L

NIH Unit
0.7-1.4 mg/dL

Reference laboratory reports in both mmol/L and mg/dL as of
March 31, 2011.
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.

Cerebrospinal fluid (CSF) L:P ratio may assist in evaluation of patients with neurologic dysfunction and normal blood L:P ratios. Blood and CSF specimens should be collected at the same time.
Comments:
This test is useful for investigating possible disorders of mitochondrial metabolism, when used in conjunction with blood lactate collected at the same time to determine the lactate-to-pyruvate ratio.

Cautions:
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. The determination of pyruvic acid is of diagnostic value when lactic acid is measured and the L:P ratio is established in the same specimen.

When comparing blood and cerebrospinal fluid (CSF) L:P ratios, blood and CSF specimens should be collected at the same time.
Methodology:
Spectrophotometry (SP)
CPT Code:
84210