Establishment and Clinical Application of a Highly Sensitive Time-Resolved Fluorescence Immunoassay for...

To establish a rapid and highly sensitive assay for tumor-associated trypsinogen-2 (TAT-2) based on the time-resolved fluorescence immunoassay (TRFIA) and evaluate its potential clinical value in patients with lung cancer. The double-antibody sandwich method was used in detecting TAT-2 antigen concentrations, and two types of TAT-2 antibodies (coating antibodies and Eu³⁺ labeled antibodies) were used. A TAT-2-TRFIA method was then established, evaluated, and used in detecting the serum TAT-2 levels of healthy subjects and patients with lung cancer. The linear range of the TAT-2-TRFIA method was 1.53-300 ng/mL, the intra-assay coefficient of variation (CV) were between 1.67% and 8.42%, and the inter-assay CV were between 4.29% and 11.44%. The recovery rates of TAT-2-TRFIA were between 99.17% and 107.06%. The cross-reactivities of trypsin and T-cell immunoglobulin mucin 3 were 0.02% and 0.82%, respectively. The serum TAT-2 levels of patients with lung cancer were higher than those of healthy subjects (P < 0.001). Combined with TAT-2, the sensitivity and specificity of CEA and CA-125 for lung cancer improved significantly. Conclusion: We successfully established a highly sensitive TAT-2-TRFIA method, which was able to facilitate the timely diagnosis of lung cancer.