A sandwich method of enzyme immunoassay. III. Assay for human beta-2 microglobulin compared with radioimmunoassay

A sandwich enzyme immunoassay has been developed to measure human beta-2 microglobulin (β2m) in biological fluids. β2m is first bound by specific antibody covalently coupled to microcrystalline cellulose. The solid phase is washed and reincubated with glucose oxidase-labeled anti-β2m antibody. After washing, the enzymic activity of the solid phase is measured by incubation with the appropriate chromogenic substrate. The OD is directly related to the quantity of β2m to be measured. A second sandwich assay has also been developed which uses plastic microplates coated with the IgG fraction of rabbit anti-β2m serum. Reproducible results are obtained in the range 2–150 and 0.75–48 μg/l respectively. These tests detect 17 fmoles and β2m. Assays of 27 sera showed good agreement between these two enzyme immunoassay methods and two radioimmunoassays.