Kay factors for accurate measurements of lactate and pyruvate:
(1) immediate deproteinization (typically with an equal volume of 1 molar perchloric acid) with centrifugation
(2) maintaining a physiologic pH (pH = 7) for the chemical analysis
where:
• The pH will be affected by the addition of the perchloric acid, so this must be corrected afterwards.
• The sample must be collected separately because of the addition of the perchloric acid.
• The temperature of the specimen prior to deproteinization (4°C superior to room temperature) will affect the result. The specimen should be placed in wet ice immediately.
• Significant time between collection and deproteinization (> 30 minutes) will result in an elevation of the lactate and drop in pyruvate (Table 2, page 696).
• Variation in pH primarily affects the pyruvate concentration (Table 3, page 696).
Interpretation:
• Significant changes in lactate and pyruvate may be encountered if the sample is not handled properly.
• The impact may be magnified if the lactate to pyruvate ratio is calculated. An increase in the ratio by 2-3 fold may occur simply by mishandling the specimen.
