Lactate to Pyruvate Ratio
2007935
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.
Mnemonic
LP RATIO
Methodology
Quantitative Enzymatic
Performed
Sun-Sat
Reported
1-2 days  
New York DOH Approval Status
This test is New York DOH approved.
Submit With Order
Specimen Required
Patient Preparation
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.  
Collect
Whole blood using either a syringe or green (sodium or lithium heparin), lavender (EDTA), or pink (K2EDTA).  
Specimen Preparation
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)  
Storage/Transport Temperature
Frozen.  
Unacceptable Conditions
If less than 1 mL of blood is added to collection tube, pH of the supernatant will be too low for testing.  
Remarks
  
Stability
Ambient: 8 hours; Refrigerated: 3 weeks; Frozen: 1 month  
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 artifactually 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.

See Compliance Statement B: www.aruplab.com/CS
Statement B: This test was developed and its performance characteristics determined by ARUP Laboratories. The U.S. Food and Drug Administration has not approved or cleared this test; however, FDA clearance or approval is not currently required for clinical use. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions.
 
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.
CPT Code(s)
84210; 83605
Components
Component Test Code*Component Chart Name
2007936Lactic Acid
2007937Pyruvic Acid
2007938Lactate to Pyruvate Ratio
* Component test codes cannot be used to order tests. The information provided here is not sufficient for interface builds; for a complete test mix, please click the sidebar link to access the Interface Map.
Aliases
  • Lactate Pyruvate Ratio
  • LP Ratio
  • Pyruvate (Pyruvic Acid)