[Establishment of BA-ELISA method for detecting CEA in human sera].

Aim: To establish a sensitive biotin-avidin enzyme linked immunosorbent assay (BA-ELISA) method for detecting carcinoembryonic antigen (CEA) in serum.

Methods: CEA which had been purified by affinity chromatography was used to immunize the rabbits to produce polyclonal antibodies. Then the antibodies were connected with biotin and horseradish peroxidase (HRP). So BA-ELISA method was established on the basis of 96 microwell plates coated with biotinylated BSA. Finally we examined the sensitivity, specificity, stability and recovery rate of this system and compared the BA-ELISA method with the traditional ELISA, radioimmunoassay and chemiluminescence in detecting CEA concentrations.

Results: The stability of this system was proved good. The linear range was from 0.42 to 50 U/mL, the sensitivity was 0.42 U/mL, and the intra-differences together with inter-differences were less than 10.0%. There was significant difference between BA-ELISA and traditional ELISA, while there was no significant difference between BA-ELISA and radioimmunoassay. The regression equation of this method was y=0.04825+0.99674x and r=0.994, and there was no significant difference between the BA-ELISA and chemiluminescence.

Conclusion: The BA-ELISA method we established to detect CEA was easy to operate, highly sensitive, low in price and suitable for application in clinical detection.