For accurate lactate determinations in plasma, which anticoagulant combination is preferred?

For accurate lactate determinations in plasma, which anticoagulant combination is preferred?

• A. Sodium heparin
• B. Sodium citrate
• C. EDTA
• D. Oxalate plus fluoride

Answer: (D)

The key idea is to stop glycolysis after blood is drawn so the measured lactate reflects the patient’s level, not ongoing cellular metabolism in the sample. The fluoride-oxalate combination does this best: fluoride inhibits glycolysis (slowing or stopping the production of lactate by cells in the sample), while oxalate prevents clotting so you obtain plasma rather than serum. Because other anticoagulants like heparin, citrate, or EDTA don’t inhibit glycolysis, lactate can continue to be produced ex vivo and falsely elevate the result. Using fluoride-oxalate thus provides a more accurate plasma lactate measurement. Keep in mind to handle samples promptly and, if possible, place them on ice to minimize any remaining metabolic activity.

The key idea is to stop glycolysis after blood is drawn so the measured lactate reflects the patient’s level, not ongoing cellular metabolism in the sample. The fluoride-oxalate combination does this best: fluoride inhibits glycolysis (slowing or stopping the production of lactate by cells in the sample), while oxalate prevents clotting so you obtain plasma rather than serum. Because other anticoagulants like heparin, citrate, or EDTA don’t inhibit glycolysis, lactate can continue to be produced ex vivo and falsely elevate the result. Using fluoride-oxalate thus provides a more accurate plasma lactate measurement. Keep in mind to handle samples promptly and, if possible, place them on ice to minimize any remaining metabolic activity.