Serum creatinine levels measured by the Jaffe and enzymatic
methods were similar in both the healthy (0.79 ± 0.16 vs. 0.79 ±
0.15 mg/dL, respectively, P = 0.76), and the diabetic (0.96 ± 0.22
vs. 0.92 ± 0.29 mg/dL, P = 0.17; Fig. 1) groups, and was significantly
higher in the diabetic patients (P b 0.001), despite similar measured
GFRs between groups (115 ± 24 vs. 107 ± 29 mL/min/1.73 m2,
respectively in healthy and diabetic patients, P = 0.097). The correlation
between the two creatinine methods was strong and statistically
significant in both groups. However, it was higher in the healthy
group (r = 0.90 vs. 0.76, P b 0.001; Fig. 2, panels at left). The agreement
between Jaffe and enzymatic creatinine methods in the sample
as a whole is shown in Fig. 2 (panels at right).