Individual renal clearance measurements in man using the early part of 131I-hippuran renogram. Comparison with 197HgCl2 fixation

Quantitative measurement of individual renal function was assayed using analysis of the early part of 131I-Hippuran uptake curve obtained from single probes over kidneys and subclavicular area and recorded on magnetic tape. Blood background substraction was performed by calibration of the blood curve with a prior 131I-Albumin injection. Postulating the same detection efficiency for each kidney by a previous 125I-Hippuran injection, we calculated the clearance ratio as the ratio of the angular coefficient of the early part of the corrected renogram against the corresponding blood integral activity curve. Data processing was performed without any preimposed model. Individual clearances were calculated from the total clearance simultaneously measured using the simplified method without urine collection. In 7 control subjects, clearances expressed in per cent of total clearance, were 51.2+-1.3 and 48.3+-1.4 ml/min for right and left kidney respectively. In 4 uninephrectomized patients a precision of 5% in calculating individual clearance was estimated from data recorded at the level of the remaining kidney. In 8 patients with functional asymmetry, results were compared with 197Hg Cl2 fixation. A correlation coefficient of 0.95 was found. The method we propose seems valuable for clinical investigation, allowing repetitive measurements