The Glucose Interference in Creatinine Measurement Using an Enzymatic Method: Effect of Creatinine Concentrations
Charoan Kaitwatcharachai MD*, Somthawil Kaitwatcharachai BNS**, Jaruda Aeden BSc ***, Dullached Wiriyasombat BSc***
Affiliation : * Division of Medicine, Hat-Yai Hospital, Songkhla, Thailand ** Division of Nursing, Hat-Yai Hospital, Songkhla, Thailand *** Division of Clinical Pathology, Hat-Yai Hospital, Songkhla, Thailand
Objective : To evaluate the influence of glucose and creatinine concentrations on the determination of creatinine by Jaffe
picrate reaction and specific enzymatic assay.
Material and Method: Unused dialysate with 4.25% dextrose was diluted to obtain seven glucose concentrations. Two series
of dialysate were spiked with creatinine to yield concentrations of 5 and 10 mg/dl. Creatinine measurements were obtained by
Jaffe method and enzymatic assay.
Results : In unused dialysate solution with glucose concentrations from 559 to 4,250 mg/dl, the creatinine values obtained by
the Jaffe method were higher than the enzymatic assay (0.31 + 0.20 vs. 0.08 + 0.01 mg/dl, p < 0.05). The correlation
coefficient between glucose and creatinine from the Jaffe method were 0.98 (p < 0.001) but showed no correlation with
creatinine measured with the enzymatic assay. On the other hand, the mean values of creatinine in dialysate with creatinine
concentrations of 5 and 10 mg/dl derived by Jaffe method were lower than enzymatic assay (5.74 + 0.12 vs. 6.16 + 0.36 mg/
dl and 11.56 + 0.17 vs. 12.69 + 0.66 mg/dl, respectively). At creatinine concentration of 10 mg/dl, the correlation between
glucose concentration and creatinine from enzymatic assay was significant. In contrast, at creatinine concentration of 5 mg/
dl, the correlations obtained from both methods were significant.
Conclusion : The patterns of glucose interference with creatinine obtained from Jaffe method and enzymatic assay were quite
different. The magnitude of interference with enzymatic assay was greater at a higher creatinine concentration. Therefore, the
enzymatic assay might not be appropriate for creatinine measurement in patients using dialysate with dextrose 4.25% and
membrane characteristic of high solute transporter.
Keywords : Creatinine measurement, Dialysate, Jaffe alkaline picrate reaction, Specific enzymatic assay
