Lactate to Pyruvate Ratio, Whole Blood
Also known as: LP RATIO
Use
The blood lactate to pyruvate (L:P) ratio is used to distinguish between pyruvate dehydrogenase deficiency and other causes of congenital lactic acidosis. In conjunction with an elevated lactate, an L:P ratio greater than 30 suggests inherited disorders of the respiratory chain complex or tricarboxylic acid cycle disorders. In conjunction with an elevated lactate, an L:P ratio less than 25 suggests a defect in pyruvate metabolism. Abnormal concentrations of lactate, pyruvate, and the L:P ratio are not diagnostic for any single disorder and must be interpreted in the context of the individual's clinical presentation and other laboratory studies.
Special Instructions
Patient should be fasting and at complete rest. Patient should avoid any exercise of the arm or hand before or during collection. Draw the specimen without the use of a tourniquet or within three minutes of applying the tourniquet, but before releasing the tourniquet.
Limitations
An artificially high L:P ratio can be observed in acutely ill individuals. If addition to perchloric acid is delayed, lactate concentration of whole blood increases by approximately 30 percent after 30 minutes, 50 percent after 1 hour, and 75 percent after 2 hours at room temperature. If less than 1 mL of blood is added to the collection tube, the pH of the supernatant will be too low for testing.
New York Approved
Methodology
Automated Analyzer (Clinical Chemistry)
Biomarkers
LOINC Codes
- 14121-8
- 2550-2
- 32693-4
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
1 mL
Minimum Volume
1 mL
Container
Green (Sodium or Lithium Heparin) tube
Collection Instructions
Immediately after blood is drawn, add exactly 1 mL whole blood to a chilled pyruvate collection tube containing 2 mL 8 percent (w/v) perchloric acid. Mix well for 30 seconds then place in an ice bath for 10 minutes. Centrifuge for 10 minutes at 1500 x g. Decant 2 mL supernatant to an ARUP Standard Transport Tube and freeze.
Patient Preparation
Patient should be fasting and at complete rest. Avoid any exercise of the arm or hand before or during collection. Draw the specimen without the use of a tourniquet or within three minutes of applying the tourniquet, but before releasing the tourniquet.
Storage Instructions
Frozen.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | Unacceptable |
| Refrigerated | 2 days |
| Frozen | 4 weeks |
Other tests from different labs that may be relevant