Abstract
Objective: The aim of the study was to develop and validate an easily available and robust enzymatic method for determination of D-lactate in blood plasma and urine. The developer method was used for the evaluation of plasmatic D-lactate levels in patients in perioperative care.
Design: The article describes the methodology and preents the results of a prospective, observational study. Settings: Center for Research and Development, University Hospital Hradec Králové.
Material and Methods: Blood plasma was deproteinated by ultrafiltration; urine may be analysed directly. The principle of the method is the coupled reaction of D-lactate dehydrogenase reducing nicotinamide adenine dinucleotide and D-glutamate pyruvate transaminase.
The end point concentration of nicotinamide adenine dinucleotide is determined as absorbance at 340 nm. The patient cohort consisted of 117 patients operated for colorectal cancer.
The blood samples were collected preoperatively, 2 hours after operation, and daily from the first to the fourth postoperative day. Data are presented as median (interquartile range).
Results: The precision achieved in plasma was 1.5-4.9 %. A quantification limit of 10 umol/L and detection limit of 5 umol/L were found.
The method is linear from 10 umol/L to 1 mmol/L. Basal preoperative values of 33.4 (26.4; 39.7) umol/L increased within two hours postoperatively to 90.2 (78; 101) umol/L, and D-lactate concentration peaked on the first postoperative day.
The concentration returned to basal values on the fouth day. Conclusion: The desribed method may be used widely in clinical chemistry laboratories due to its availability, robustness and simplicity, wherever D-lactate testing is required.