Automated immunofluorometric assay for MUC1

The aim of the present study was to establish a robust, reliable and fully automated immunofluorometric assay for the breast cancer serum marker MUC1. This would further serve as a prototype assay for evaluation of other MUC1 assays based on new antibody combinations. Using time-resolved fluorescenc e as tracer signal we developed an automated immunofluorometric assay for M UC1 (MUC1 IFMA). This assay was compared with two commercial assays. The CA 15-3 EIA (CanAg) which use the same antibodies as the MUC1 IFMA, and the ET I-CA-15-3 K (Sorin) which use the original antibodies defining the CA 15-3 assay. The three assays showed comparable results. The coefficient of varia tion was below 10% from 9 to 2,400 kU/I for the MUC1 IFMA, from 15 to 250 k U/I for the CA15-3 EIA, and from 25 to 200 kU/I for the ETI-CA-15-3 K assay . At a specificity of 0.94 the overall diagnostic sensitivities for the MUC 1-IFMA, CA15-3 EIA and ETI-CA-15-3 K assays were 0.40, 0.37, and 0.38, resp ectively. When applied to metastatic breast cancer, all assays had sensitiv ities close to 0.80. There was a close correlation (Spearman rank = 0.99) b etween results from the new assay and the CA15-3EIA. The new automated assa y was not strictly immunometric as we could not achieve conditions where so lid phase or tracer antibodies were in apparent excess. However, the assay performed well at a wide range of assay conditions. The automation, which m inimizes imprecision in pipetting and handling of samples, and the high cap acity of th e Auto DE LF IA instrument enabling measurement of all samples in a single run, were important aspects for establishing a reliable assay. The principle of the new automated immunofluorometric assay will be used as a rapid and reliable evaluation of a wide range of monoclonal antibody com binations in our search for the optimal MUC1 assay. This new automated immu nofluorometric assay will be useful in the rapid and reliable evaluation of a wide range of monoclonal antibody combinations in our search for the opt imal MUC1 assay. Copyright (C) 2001 S. Karger AG. Basel.