Screening of Kidney Function by Plasma Creatinine and Single-Sample ⁵¹Cr-EDTA Clearance Determination–A Comparison

Abstract

Nomograms or simple formulas have been suggested for estimating the glomerular filtration rate (GFR) from either plasma creatinine (Cl_K) or from a single plasma sample drawn after an intravenous injection of ⁵¹Cr-EDTA (Cl_A/B)- This study compares the precision of estimating GFR as Cl_K and Cl_A/B-A multiple plasma-sample standard method (Cl_SM) served as reference. The comparison was performed in 136 individuals. The variance of Cl_AJB on Cl_SM was 14.4 ml/min/1.73 m² while the variance of C1_K on Cl_SM was 204.5 ml/min/1.73 m². It is concluded that the Cl_A/B values are more precise than the C1_K values (p<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 C1_SM.

Key Words:

• ⁵¹Cr-EDTA clearance
• glomerular filtration rate
• plasma creatinine
• renal function