Sign in →

Test ID: PYRC Pyruvate, Spinal Fluid

Reporting Name

Pyruvic Acid, CSF

Useful For

Investigating possible disorders of mitochondrial metabolism, when used in conjunction with cerebrospinal fluid lactate, collected at the same time, to determine the lactate-to-pyruvate (L:P) ratio

 

Evaluating patients with neurologic dysfunction and normal blood L:P ratios

Clinical Information

Pyruvic acid, an intermediate metabolite, plays an important role in linking carbohydrate and amino acid metabolism to the tricarboxylic acid cycle, the fatty acid beta-oxidation pathway, and the mitochondrial respiratory chain complex. Though pyruvate is not diagnostic in itself, analysis with lactate has diagnostic value as many inborn errors of metabolism present with laboratory findings that include lactic acidosis and/or a high lactate:pyruvate (L:P) ratio.

 

The L:P ratio is elevated in several, but not all, mitochondrial respiratory chain disorders. Mitochondrial disorders vary widely in presentation and age of onset. Many mitochondrial disorders have neurologic and myopathic features and may involve multiple organ systems. Determination of lactate, pyruvate, and the L:P ratio in cerebrospinal fluid is helpful in directing attention toward a possible mitochondrial disorder in cases with predominantly neurologic dysfunction and normal blood lactate levels.

 

A low L:P ratio is observed in inherited disorders of pyruvate metabolism including pyruvate dehydrogenase complex (PDHC) deficiency. Clinical presentation of PDHC deficiency can range from fatal congenital lactic acidosis to relatively mild ataxia or neuropathy. The most common features in infants and children with PDHC deficiency are delayed development and hypotonia. Seizures and ataxia are also frequent features. Other manifestations can include congenital brain malformations, degenerative changes including Leigh disease, and facial dysmorphism.

Interpretation

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 above 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 below 10.

 

The L:P ratio is characteristically normal in other patients. An artifactually high ratio can be found in acutely ill patients.

Testing Algorithm

See Epilepsy: Unexplained Refractory and/or Familial Testing Algorithm in Special Instruction.

Analytic Time

6 days

Day(s) and Time(s) Performed

Monday, Thursday; Varies

Clinical Reference

1. Munnich A, Rotig A, Cormier-Daire V, Rustin P: Clinical Presentation of Respiratory Chain Deficiency. In The Online Metabolic and Molecular Bases of Inherited Disease. Edited by D Valle, S Antonarakis, A Ballabio, et al. McGraw-Hill. Accessed 1/13/2020. Available at http://ommbid.mhmedical.com/content.aspx?bookid=2709&sectionid=225086827

2. Robinson BH..Lactic Acidemia: Disorders of Pyruvate Carboxylase and Pyruvate Dehydrogenase. In The Online Metabolic and Molecular Bases of Inherited Disease. Edited by D Valle, S Antonarakis, A Beaudet, et al. McGraw-Hill. Accessed 1/13/2020. Available at http://ommbid.mhmedical.com/content.aspx?bookid=2709&sectionid=225087140

3. Shoffner JM: Oxidative Phosphorylation Diseases. In The Online Metabolic and Molecular Bases of Inherited Disease. Edited by D Valle, S Antonarakis, A Ballabio, et al. McGraw-Hill. Accessed 1/13/2020. Available at http://ommbid.mhmedical.com/content.aspx?bookid=2709&sectionid=225088339

Method Name

Spectrophotometry (SP)

Specimen Type

CSF


Additional Testing Requirements


This test does not calculate the lactate:pyruvate ratio. To obtain this information, both this test and LABF / Lactate, Body Fluid must be ordered. The ratio can be calculated from the results obtained from these tests.



Specimen Required


Container/Tube: Sterile vial

Specimen Volume: 0.6 mL

Collection Instructions: Send specimen from vial 2.


Specimen Minimum Volume

0.3 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
CSF Frozen (preferred) 7 days
  Ambient  7 days
  Refrigerated  7 days

Reference Values

0.06-0.19 mmol/L

Test Classification

This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. This test has not been cleared or approved by the U.S. Food and Drug Administration.

CPT Code Information

84210

LOINC Code Information

Test ID Test Order Name Order LOINC Value
PYRC Pyruvic Acid, CSF 14122-6

 

Result ID Test Result Name Result LOINC Value
83356 Pyruvic Acid, CSF 14122-6

Forms

1. Biochemical Genetics Patient Information (T602) in Special Instructions.

2. If not ordering electronically, complete, print, and send an Inborn Errors of Metabolism Test Request (T798) with the specimen.

Mayo Clinic Laboratories | Neurology Catalog Additional Information:

mml-Pediatric, mml-Neurometabolic