Quantitative hippurate renography.

Effective renal plasma flow (ERPF) was determined by registration of 131I-hippurate radioactivity over the heart and calculation of the disappearance constants after fitting a three-exponential function to the measured time-activity curve. Right and left kidney ERPF was calculated both by a method of tangents and a new method of summed pulses from the time interval 1-2 min after injection of the tracer. The summed pulses method is less prone to errors and is therefore recommended for use in clinical practice. Age-dependent reference values for ERPF are reported.