Performance on immunoglobulin IgG, IgA, and IgM tests in CAP survey specimens

The performance of participants in nine consecutive College of American Pathologists (CAP) Survey specimens during 1979-1981 are listed for IgA, IgG, and IgM. The majority of participants used either radial immunodiffusion (RID) (51.4%) or nephelometric kits (33.6 per cent) manufactured by major firms and reported results in mass units (93.5 per cent). When tabulated by kit, prominent differences in performance were noticed. Furthermore, definite trends in methods employed were evident during the two-year period.