Serum Creatinine Determined by Jaffe, Enzymatic Method, and Isotope Dilution-Liquid Chromatography-Mass Spectrometry in Patients Under Hemodialysis

Objectives: Serum creatinine is an important clinical marker for renal clearance. However, the Jaffe method had much interference and the accuracy had not been tested in patients under hemodialysis (HD) with standard isotope dilution-liquid chromatography-mass spectrometry (IDLCMS) method. The validity of enzymatic method is also unknown. Methods: The predialysis serum creatinine levels of 126 patients under regular HD for 3 months were checked by Jaffe, enzymatic, and IDLCMS methods. We compared the value of the Jaffe and enzymatic to that of IDLCMS in linear regression model. And we also tried to find the clinical parameters that influence the difference between Jaffe vs. IDLCMS and enzymatic vs. IDLCMS method. Results: We found significant underestimate serum creatinine in uremic patients by Jaffe and enzymatic methods. Serum glucose and globulin are positive biases, whereas albumin, potassium, and phosphorus are negative biases. Enzymatic method is less affected by serum glucose and serum protein. Albumin acts differently in uremic serum compared to the results of mixing them with normal serum. Conclusions: For uremic patients, in whom creatinine level is high and many of them suffered from diabetes mellitus, serum creatinine can be either under- or overestimated by Jaffe method. Enzymatic method is less affected and may be a better method.