Over-estimation of glomerular filtration rate by single injection [51Cr]EDTA plasma clearance determination in patients with ascites

Abstract

The total plasma (Clt) and the renal plasma (Clr) clearances of [51Cr]EDTA were determined simultaneously in 9 patients with ascites due to liver cirrhosis. Clt (mean 78 ml/min, range 34-115 ml/min) was significantly higher than Clr (mean 52 ml/min, range 13-96 ml/min, P < 0.005). The ascitic fluid-plasma activity ratio of [51Cr]EDTA increased throughout the investigation period (5 h). [51Cr]EDTA apparently equilibrates slowly with the peritoneal space indicating Clt will probably overestimate the glomerular filtration rate by approximately 20ml/min in patients with ascites. To assess glomerular filtration rate in presence of ascites, the renal plasma clearance of [51Cr]EDTA should be used instead of the total plasma clearance.