Preparation and preliminary application of double antibody sandwich ELISA for CYFRA21-1

Objective:To establish the detection method of double-antibody sandwich ELISA about CYFRA21-1 in human serum. Methods: The paired antibody were screened among four strains mAbs of CYFRA21-1,which was marked by sodium periodate method. The detecting method of double antibody sandwich ELISA was optimizted,and evaluated by specificity,stability and sensitivity. Results: The results showed that a paired of antibody,which was 2F9 as the coated antibody and 6F11 as the labeled antibody, was selected from four mAbs. It was the optimum condition of double antibody sandwich ELISA that the coating antigen concentration of 2F9 was 0. 50 μg / ml,while the labeled antibody of 6F11 was diluted 6 000 times. The linear range of standard curve was 0. 7-25 ng / ml with r2= 0. 990 8,while the limit of detection was 0. 666 8 ng / ml,the recovery rate was 98. 14%. The cross-reactions with the other analogues in serum were less than 0. 1%. The coefficient of variation in group( n = 10) was 6. 8%,whereas coefficient of variation among group( n = 5) was 11. 4%. The correlation compared with other foreign ELISA kit was 91. 42%. Conclusion: In brief,we successfully established the method of double antibody sandwich ELISA detecting CYFRA21-1 level in human serum,laying the foundation for the production of CYFRA21-1 ELISA kit.