A Study on the Appropriate Normal Range of Serum Creatinine Level for Koreans

Abstract

Background: Early identification and appropriate management of mild chronic renal failure has been increasingly recognized as an important opportunity to delay the progression of renal disease. Many physicians rely on serum creatinine (Scr) as a screening test for renal impairment; however, Scr levels can remain within the normal range even when renal function is significantly impaired in certain group of patients.

Methods: The subjects were 20,245 persons who were enrolled a regular health check up program, Jan. 1997 to Jun. 2001, at Ajou University Hospital, Korea. We identified GFR below 60 mL/min/1.73 m² as abnormal and found the percentage of patients with Scr value from 1.1 mg/dL to 1.4 mg/dL and their sex and age distribution, using GFRs calculated by Cockroft-Gault Equation, MDRD Equation, and Kang’s Equation.

Results: Average Scr was 1.07±0.13 mg/dL in male and 0.82±0.11 mg/dL in female. Among 34 University hospital in metro Seoul area, 11 hospital used 1.4 mg/dL as normal upper limit of Scr and 7 hospital used 1.3 mg/dL. Taking normal Scr upper limit as 1.3 or 1.4 mg/dL, the frequency of GFR below 60 mL/min/1.73 m² was 3.9-50% in males and 75-100% in females, although some differences existed according to the equation used.

Conclusion: Currently used normal Scr upper limit 1.3, 1.4 mL/dL was found to be much too high and we concluded a downward adjustment is needed and one-time test is not adequate to conclude renal impairment but several regular tests are required.