Establishment of a chemiluminescent immunoassay for cancer antigen 125

Objective To establish a chemiluminescent immunoassay for determining cancer antigen 125(CA125)in human serum. Methods Using two-antibodies sandwich enzyme immunoassay,one monoclonal antibody was coated to a microplate,and a polyclonal antibody was conjugated with alkaline phosphatase.In the same time,the conjugation was performed by optimized NaIO4 method.Chemiluminescent immunoassay was established using CSPD and Sapphire Ⅱ luminescent system.Sensitivity,specificity,linear scope,precision,interference and recovery for the method were evaluated.The reference range was defined by testing 500 serum samples of healthy subjects.The data of 126 serum samples of patients were assayed by chemiluminescent immunoassay,and the relation with the results by the Bayer ACS:180(automated immunoassay system)was analyzed. Results The sensitivity was 0.1 U/ml.The specificity was 100%.The linear scope was 0.1-960.0 U/ml.Average inter and intra precisions were 3.6% and 5.3%,respectively.The recoveries ranged from 86.5% to 96.2%.The cross-reacting rates for CA50,CA153,CA199,CEA were≤0.1%,0.1%,0.5% and 0.1%,respectively.The results assayed by chemiluminescent immunoassay was positively related to the results by ACS:180 kit of Bayer Co.(r=0.993,P0.001). Conclusion A successfully established chemiluminescent immunoassay is a feasible way for clinically determining CA125 with dependable results.