Screening of kidney function by plasma creatinine and single-sample 51Cr-EDTA clearance determination--a comparison

Nomograms or simple formulas have been suggested for estimating the glomerular filtration rate (GFR) from either plasma creatinine (ClK) or from a single plasma sample drawn after an intravenous injection of 51Cr-EDTA (ClA/B). This study compares the precision of estimating GFR as ClK and ClA/B. A multiple plasma-sample standard method (ClSM) served as reference. The comparison was performed in 136 individuals. The variance of ClA/B on ClSM was 14.4 ml/min/1.73 m2 while the variance of ClK on ClSM was 204.5 ml/min/1.73 m2. It is concluded that the ClA/B values are more precise than the ClK values (p less than 0.01). The single-sample method for determination of 51Cr-EDTA clearance seems well-suited for evaluation and monitoring of patients with known or suspected kidney diseases. It may even be applied for screening purposes in cases where plasma creatinine would otherwise have been chosen instead of the usual resource-demanding method for determination of ClSM.