An enzyme immunoassay for carcinoembryonic antigen which employs simultaneous incubation of specimen with solid phase and enzyme-conjugated antibodies.

The Abbott CEA-EIA Monoclonal One-Step procedure was evaluated and compared to the Abbott CEA-EIA Monoclonal, a two-step assay. The reproducibility, sensitivity, recovery and dilution linearity were similar for both assays. Excellent correlations were found between the carcinoembryonic antigen (CEA) values obtained with these assays for healthy donors (n = 261, r = 0.951), patients with benign diseases (n = 171, r = 0.994) and cancer patients (n = 585, r = 0.997). In serial monitoring studies, one-step CEA values paralleled the CEA values determined with the two-step assay regardless of the type of cancer. The advantages of the one-step CEA assay over the two-step assay include significant reduction in both attended and total assay times, reduced sample volume, dry antibody-coated beads, color-coded reagents and an extended range for the standard curve. These test improvements were achieved without affecting the reproducibility, sensitivity and accuracy of the CEA measurement.