Serum Creatinine Determination: Comparison between Colorimetric (Jaffé) and Enzymatic Methods in Renal Transplant Recipients

Background: Serum creatinine is the most requested parameter in current practice in the context of functional exploration of the kidney. Its contribution to medical care is particularly decisive for kidney transplant patients. The aim of the study is to compare the colorimetric and enzymatic techniques available in our laboratory for the determination of creatinine in samples from kidney transplant patients.

Methods: Prospective study carried out at the Biochemistry laboratory of the University Hospital Center (CHU) Ibn Rochd in Casablanca Morocco, over a period of 8 months, carried out on a series of 45 samples from kidney transplant patients who simultaneously benefited from a creatinine assay by colorimetric and enzymatic techniques. The samples were taken on dry tubes and analyzed on the Alinity ® Abbott analyzer. The statistical study of correlation was made by the SPSS software with calculation of the p-value and the coefficient of Pearson (r).

Results: During the study period 45 samples were collected. Seventy percent of the prescriptions came from the Nephrology Department. The mean serum creatinine value by enzymatic technique was 39.04 ± 11.7 mg/l, and by colorimetric technique 38.24 ± 12.4 mg/l. The creatinine level by the two techniques was pathological in 69% of cases and normal in 31%. The correlation between the serum creatinine assay by enzymatic Versus colorimetric technique is positive with r=0.994 and P-value<0.001.

Conclusion: According to literature, colorimetric techniques are sensitive to interference with pseudochromogenic substances, while enzymatic techniques are standardized due to their specificity and performance but remain more expensive. In our study the correlation between the two techniques was positive with a correlation equation: (y = 0.82 + 1*x). According to our results, no significant difference between the two techniques was observed in our laboratory.