Single injection (51Cr)EDTA plasma clearance determination in children using capillary blood samples.

The reliability of a determination of the total [51Cr]EDTA plasma clearance (E) (and with it the glomerular filtration rate), by a simplified single injection method (injected dose: 4.5 muCi per kg b.w.) using capillary blood samples (0.2 ml), was investigated in twenty children. Clearance values determined from capillary blood samples did not differ significantly from those measured simultaneously from venous blood samples, the mean ratio +/-SD being 1.02 +/- 0.06 (n = 10). The reproducibility (total day-to-day variation) of E determined from capillary blood samples was 6.7% in children with decreased renal function (n = 3) and 6.9% in children with normal renal function (n = 7). The present data indicate that the use of capillary blood samples is an accurate and very precise approach for determination of E in children.