Radioimmunoassay of beta2-microglobulin.

A radioimmunoassay for quantitation of beta2-microglobulin in serum and urine is described. Polyethylene glycol 6000 was used to precipitate the antigen-antibody complex. The assay can be performed within 5 hr. In healthy human subjects (mean age, 30.6 years and 42.0 years for serum and urine determinations, respectively) the mean concentration of beta2-microglobulin in serum was 125 nmol/l (range, 49-190 nmol/l). In men the mean 24-hr urinary excretion was 12.9 nmol (range, 8.6-19.2 nmol), and in women it was 5.5 nmol (range, 2.9-8.7 nmol). The assay range was 0.23-19.40 nmol/l, and the detection limit was 0.042 nmol/l, using a prolonged incubation time. The coefficient of variation based on 20 determinations in serum dilutions with a concentration of beta2-microglobulin of 8.14 and 1.92 nmol/l was 8.1 per cent and 9.0 per cent, respectively.