THE TECHNIQUE of radioimmunoassay (RIA) is currently the most popular method for measurement of hormone levels in plasma or serum. Radioimmunoassay combines excellent sensitivity with precision and freedom from interference. However, subtle differences in RIA procedures can make a substantial difference in the reliability of this technique on serum or plasma samples from nephrotic patients. We report a case that shows repeated false elevations of β-human chorionic gonadotropin (β-HCG) levels during a period of nephrosis. Report of a Case A 17-year-old girl was seen because of gross edema of one to two weeks' duration. There was no history of renal disease or a recent known precipitating event. Her last menses had been approximately three months previously, and there had been at least one subsequent exposure to pregnancy. Urine pregnancy tests of unknown type done elsewhere during the previous week were said to be positive. Examination revealed generalized edema, with a
