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Lactate to Pyruvate Ratio, Whole Blood
Ordering Recommendation
When considering pyruvic acid testing, this is the preferred test. This test reports concentrations for lactate, pyruvate, and the L:P ratio on the same specimen.
New York DOH Approval Status
Specimen Required
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.
Green (Sodium or Lithium Heparin).
If whole blood is collected in a syringe, transfer immediately to green (sodium or lithium heparin) tube before preparing specimen.
1) 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 (ARUP supply #16567) available online through eSupply using ARUP Connect™ or contact Client Services at (800) 522-2787.
2) Mix well for 30 seconds then place in an ice bath for 10 minutes.
3) Centrifuge for 10 minutes at 1500 x g.
4) Decant 2 mL supernatant to an ARUP Standard Transport Tube and freeze. (Min: 1 mL)
Frozen.
Ambient: Unacceptable; Refrigerated: 2 days; Frozen: 4 weeks
Methodology
Quantitative Enzymatic Assay
Performed
Sun-Sat
Reported
1-2 days
Reference Interval
| Available Separately | Components | Reference Interval |
|---|---|---|
| No | Lactate | 0.31-2.00 mmol/L |
| No | Pyruvate | 0.030-0.107 mmol/L |
| No | L:P Ratio | Not Applicable |
Interpretive Data
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. An artificially high L:P ratio can be observed in acutely ill individuals. 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.
This test was developed and its performance characteristics determined by ARUP Laboratories. It has not been cleared or approved by the US Food and Drug Administration. This test was performed in a CLIA certified laboratory and is intended for clinical purposes.
Laboratory Developed Test (LDT)
Note
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 collection tube, pH of the supernatant will be too low for testing.
Hotline History
CPT Codes
84210; 83605
Components
| Component Test Code* | Component Chart Name | LOINC |
|---|---|---|
| 2007936 | Lactic Acid | 32693-4 |
| 2007937 | Pyruvic Acid | 14121-8 |
| 2007938 | Lactate to Pyruvate Ratio | 2550-2 |
Aliases
- Lactate Pyruvate Ratio
- LP Ratio
- Pyruvate (Pyruvic Acid)
