Henriksen, Ulrik Lütken2; Kanstrup, Inge-Lis4; Henriksen, Jens Henrik Sahl4
1 Department of Clinical Medicine, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet2 unknown3 Section of Diagnostic Sciences, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet4 Section of Diagnostic Sciences, Department of Clinical Medicine, Faculty of Health and Medical Sciences, Københavns Universitet
Abstract Background and aim. From a clinical point of view determination of glomerular filtration rate (clearance) is important. The aim of the present study was to compare the one-sample clearance to reference multiple-sample (51)Cr-EDTA clearance in consecutively referred children suspected of or with established nephro-urological disorders. Material and methods. A total of 75 children, age ½-13 years, received a quantitative intravenous injection of (51)Cr-EDTA followed by six plasma samples 10-120 min after injection. The multiple-sample clearance was measured as injected dose relative to the area under the plasma radioactivity curve. The one-sample clearance was determined from a single plasma sample collected at 60, 90 or 120 min after injection according to the one-pool method. Results. The overall accuracy of one-sample clearance was excellent with mean numeric difference to the reference value of 0.7-1.7 mL/min. In 64 children, the one-sample clearance was within ± 4 mL/min of the multiple-sample value. However, in 11 children the numeric difference exceeded 4 mL/min (4.4-19.5). Analysis of age, body size, distribution volume, indicator retention time, clearance level, curve fitting, and sampling time could not explain the observed large difference between one-sample and multiple-sample clearance in these 15% of the children. Conclusion. In the majority of children there is an excellent agreement between one-sample clearance and multiple-sample clearance. However, unexpectedly in a small fraction (15%) larger discrepancies are found. If an accurate clearance value is essential a multiple-sample determination should be performed.
Scandinavian Journal of Clinical and Laboratory Investigation, 2013, Vol 73, Issue 6, p. 466-475