Validation of a particle enhanced immunoturbidimetric assay for serum beta 2-microglobulin on the Dade aca

We describe the development and validation of a fully automated homogeneous immunoassay for serum beta 2-microglobulin on the Dade aca clinical analyzer. The assay employs latex enhanced immunoturbidimetry, with an affinity purified polyclonal antibody covalently coupled to a 40 nm latex particle. The assay working range is < 0.5 to 20 mg/l with no evidence of loss of signal due to antigen excess at concentrations up to 120 mg/l. The assay sensitivity is 0.2 mg/l; within run and between run imprecision showed coefficients of variations of < 7%, across the assay range 1-20 mg/l. A method comparison with an established RIA procedure gave a regression equation of (aca) = 1.14 (RIA)-0.26, r = 0.996, n = 109. Good analytical recovery (98-101%), no evidence of a lack of parallelism and no interference from rheumatoid factor (tested up to 1.2 x 10(6) U/l) were observed. The low method to be considered as an effective means of monitoring seroconversion in HIV infected subjects and treatment of patients with myelomatosis.