Aim: To establish a two-site time-resolved fluoroimmunoassay (TRFIA) for detection of carcino-embryonic antigen(CEA) based on the direct sandwich technique(One monoclonal antibody(mAb) is immobilized on the surface of microtiter plate strip wells, another mAb is labelled with Eu(3+)) and prepare its diagnostic reagent.
Methods: The sandwich TRFIA for detection of serum CEA level using anti-CEA mAbs was used.
Results: The measure range of CEA-TRFIA was (1-560) microg/L. The analytical sensitivity was 0.28 mug/L. The intra- and inter-assay coefficients of variation (CV) were 7.2%-8.6% and 8.9%-13.2%, respectively. There was no cross-reaction to AFP, CA12-5, CA19-9 and albumin. Cross reactivity to CA15-3 was 1.62 microg/L. The correlation coefficient of blood samples detected by CEA-TRFIA and commercially available CEA CLIA (chemiluminescent immunoassay) kit (Roche) was 0.946.
Conclusion: CEA-TRFIA is a new immunoassay which has several advantages including high sensitivity, specificity and a wide working range. It is suitable for routine clinical use.