A dual-label time-resolved fluorescence immunoassay for the simultaneous determination of carcinoembryonic antigen and squamous cell carcinoma antigen.

Among women worldwide, cervical cancer is the second-most common cancer, and cervical smears and DNA detection have low sensitivity or are too expensive. The concentrations of carcinoembryonic antigen (CEA) and squamous cell carcinoma (SCC) in the serum were detected using a sandwich immunoassay. The CEA and SCC in the serum were captured by anti-CEA and anti-SCC antibodies. After combining other anti-CEA- and anti-SCC-labeled antibodies with europium (III) (Eu3+ ) and samarium (III) (Sm3+ ) chelates, CEA and SCC were detected with time-resolved fluorometry (TRF). The linear correlation coefficients (R2 ) of the CEA and SCC standard curves were 0.9997 and 0.9997, respectively. The minimum detection level for CEA was 1.15 ng/mL (the linear dynamic range was 3.24-543.67 ng/mL), and the average recovery was 100.83%. The sensitivity for SCC detection was 0.54 ng/mL (the linear dynamic range was 2.47-96.58 ng/mL), and the average recovery was 101.02%. High R2 between the results of commercial assays and this method were obtained (R2  = 0.9983 for CEA, R2   = 0.9878 for SCC). These findings indicated that the dual-label TRFIA invented in this study has high sensitivity, accuracy, and specificity in clinical analysis, which indicates that this method could be used for the early diagnosis and follow-up surveillance of cervical cancer.