Development of a time-resolved fluoroimmunoassay kit for detecting C-peptide

Objective To develop a time-resolved fluoroimmunoassay(TRFIA) kit for detection of C-peptide in serum.Methods Two anti-C-peptide monoclonal antibodies were used to develop the sandwich TRFIA kit for detection of C-peptide in serum and its methodology was evaluated.Results The detection range of C-peptide was 0.4-20 ng/mL.The analytical sensitivity was 0.23 ng/mL.The intra-assay and inter-assay coefficients of variation were 7.99% and 11.97% respectively.The recovery rate was 99.57%.There was no cross-reactivity with insulin and proinsulin.The TRFIA C-peptide reagents could be stored at 4 ℃ for 9 months and at 37 ℃ for 7 days.The reference value for TRFIA C-peptide kit in healthy subjects(200 cases) was 0.358-3.590 ng/mL.The correlation coefficient of blood samples detection results(122 cases) between this TRFIA kit and commercially available electrochemiluminescense immunoassay C-peptide kits was 0.943 2.The linear equation was Y=0.985 4X+0.506 3.Conclusions The developed TRFIA C-peptide kit is valuable for clinical application with good sensitivity,precision,accuracy,specificity and stability.