A double antibody radioimmunoassay for human alpha 1-microglobulin

Using purified alpha 1-microglobulin from urine and specific rabbit antiserum, a double antibody radioimmunoassay has been developed. The assay is sensitive to 3 ng/ml and covers a working range from 25-800 ng/ml. The recovery rates on the average were 91.8% in serum and 97.7% in urine. The coefficients of intra-assay variation ranged from 3.6-4.5% and those of inter-assay variation from 4.0-8.8%. Correlations in serum and urine between the present assay and single radial immunodiffusion (r = 0.972; r = 0.978) and enzyme-linked immunosorbent assay (r = 0.935; r = 0.971) were satisfactory.