A RADIOIMMUNOASSAY FOR HUMAN URINARY PREALBUMIN

We describe a validated radioimmunoassay for prealbumin in urine. Usin g timed overnight urine samples, the normal reference range was less t han 10-148 mug/L; or less than 1.8-9.6 mug/mmol creatinine, excretion in women being significantly greater than in men (P<0.05); or less tha n 7.3-114 ng/min with no significant difference in excretion rate betw een the sexes. Urines exhibited loss of immunoreactivity after storage at 20-degrees-C and thawing. No such loss occurred after storage for 4 weeks at 4-degrees-C or room temperature. The urinary excretion of p realbumin was highly correlated with that of albumin (r=0.85), and cle arance relative to creatinine was 2 x 10(-6), the same order as that o f albumin.