Glomerular Filtration Rate Estimates Based on Serum Creatinine Level in Healthy People: Conventional Jaffe Method versus Calibrated Jaffe Method at Laboratories in Rasht

Conventional Jaffe method of serum creatinine measurement is influenced by several drugs and components of blood as well as the expertise of laboratory staffs. We obtained blood samples of 22 healthy volunteers and sent them to 23 laboratories in Rasht, Iran, in which the conventional Jaffe method would be used for serum creatinine measurement. Also, we tested the samples in 1 reference laboratory with the calibrated Jaffe method. Glomerular filtration rates were calculated using the abbreviated equation of the Modification of Diet in Renal Disease study. Eight of 23 laboratories (34.7%) reported significantly different mean serum creatinine levels from the mean values yielded in the reference laboratory. Seven of 23 laboratories (30.4%) had significantly different estimated glomerular filtration rates in comparison to those calculated in the reference laboratory. Different results for creatinine lead to wrong interpretation of patients’ kidney function, and rectifications of this divergence are of utmost importance.