MULTICENTER EVALUATION OF THE ABBOTT IMX(R) CA 15-3(TM) ASSAY

We describe a new fully automated procedure for the quantitative measu rement of CA 15-3: the microparticle enzyme immunoassay (MEIA) technol ogy developed by Abbott Labs, for the IMx(R) automated immunoassay ana lyzer, The new IMx CA 15-3 test uses two mouse monoclonal antibodies, 115D8 and DF3. The test has a dynamic range to 250 kilounits/L and a m inimal detectable dose of CA 15-3 <0.2 kilounits/L. On dilution, linea rity is excellent, with recoveries ranging from 94% to 101%. Studies w ere conducted at four sites to evaluate the performance characteristic s of this assay, The intra- and interassay CVs were <4.7% and <5.6%, r espectively, and showed a between-laboratory CV <5.9%. Test results of the Abbott IMx CA 15-3 (y) were correlated with those obtained with t he Centocor(R) CA 15-3 RW (x), a solid-phase heterologous RIA. Linear regression analysis on results for 1973 samples yielded: y = 0.97x - 2 .09 (r = 0.9899, S-y\x = 22.2, range 1-4089 kilounits/L).