Abstract:

Objective　 To evaluate the application of 6 creatinine-based equations of estimated glomerular filtration rate (eGFR) by enzymatic method and kinetic alkaline picric acid rate method in healthy population. Methods　 Serum creatinine was measured by enzymatic method and kinetic alkaline picric acid rate method in 694 healthy subjects. The eGFR values were calculated and compared by 6 equations [Cockcroft-Gault (C-G) equation, simplified modification of diet in renal disease (MDRD) equation, MDRD-Chinese equation, isotopic dilution mass spectrometry (IDMS)-MDRD equation, chronic kidney disease epidemiology collaboration (CKD-EPI) equation and CKD-EPI for Asian (EPI-Asian) equation]. Results　 Serum creatinine results were(65.8 ± 13.3)μmol/L[(36-117)μmol/L) for enzymatic method,(83.0 ± 12.7) μmol/L[(57-131)μmol/L] for kinetic alkaline picric acid rate method. According to eGFR reference intervals: 85-125mL/min for males and 75-115mL/min for females,if using enzymatic method to detect creatinine,the applicability in healthy subjects of 6 equations were CKD-EPI equation (72.3%)＞IDMS-MDRD equation(69.9%)＞simplified MDRD equation(61.3%)＞EPI-Asian equation (60.7%)＞C-G equation(54.8%)＞MDRD-Chinese people equation (27.3%)(P<0.05),and IDMS-MDRD equation showed the smallest difference between males and females (only 1.6%). If using kinetic alkaline picric acid rate method,the applicabilities in healthy subjects of 4 equations were MDRD-Chinese people equation(80.0%)＞EPI-Asian equation (70.1%)＞CKD-EPI equation (63.8%) ＞ simplified MDRD equation(59.1%)＞C-G equation(52.4%)＞IDMS-MDRD equation(40.7%)(P<0.05),and MDRD-Chinese people equation showed the smallest difference between males and females (only 1%). Conclusions　 There are significant differences among 6 equations. To evaluate eGFR in healthy subjects in North China,CKD-EPI equation and IDMS-MDRD equation are more applicable if using enzymatic mehod traced to IDMS to detect serum creatnine,while MDRD-Chinese people equation is more applicable if using kinetic alkaline picric acid rate method to detect serum creatnine.

Key words: Glomerular filtration rate, Creatinine, Enzymatic method, Kinetic alkaline picric acid rate method, Healthy subject