Comparison of Jaffe and enzymatic methods for creatinine estimation and their effect in GFR calculation in a tertiary care hospital

Introduction and Aim: Serum creatinine (SCr) and estimated glomerular filtration rate (eGFR) gives the idea of overall functional status of kidney. Measurement of SCr by different method and discordant result between them can misclassify different stages of chronic kidney disease (CKD). Many of the tertiary care health centre, SCr measured by Jaffe method is still the method of choice because of its cost effectiveness even if it is more susceptible for interference. Our aim was to measure SCr level by both Jaffe’s & enzymatic method and analysing the discordance rate of eGFR and their effect in staging of kidney disease in CKD patients. Materials and Methods: In this observational study 330 serum sample were analysed for creatinine by Jaffe’s and enzymatic methods in a fully automated analyser using commercially available kits. Modification of Diet in Renal Disease (MDRD) formula was used for estimating GFR. Results: In 330 subjects eGFR values calculated on incorporating SCr were found as 58.84 ± 68.34 (median (IQR) = 26.67(15.09-90.84) and 44.49 ± 41.18 (Median (IQR) = 26.86 (14.69-67.69)) ml/min/1.73 m2 respectively by Jaffe’s and enzymatic method. Concordance correlation coefficient between two methods for SCr was statistically significant. Bland-Altman plot showed with increasing value of SCr, the difference between the SCr values given by these two methods increased. Jaffe’s creatinine has lower value in comparison to enzymatic Cr. There was a significant difference between eGFR obtained from SCr estimated by Jaffe’s and enzymatic method. Conclusion: All laboratory should use uniform method for creatinine estimation. Enzymatic method for creatinine estimation should not be compromised over cost of test, so that less variability in creatinine result can lead to more accurate staging of the disease.