Abstract:

Objective To investigate the consistency and correlation between 4 domestic determination systems and ARCHITECT i2000SR automatic immunoassay analyzer with supporting reagents（i2000SR system） for determining anti-hepatitis C virus（HCV） antibody gray zone samples. Methods Totally,4 domestic determination systems [2 systems using enzyme-linked immunosorbent assay（ELISA）,1 system using time-resolved fluorescence immunoassay（TRFIA） and 1 system using chemiluminescence immunoassay（CLIA）] were used to determine different concentrations of anti-HCV antibody standard products and to evaluate the linearity of each determination system and imprecision [coefficient of variation（CV）]. The 4 domestic determination systems and the i2000SR system were used to determine 120 samples of anti-HCV antibody gray zone,which were confirmed by recombinant immunoblotting assay（RIBA） to evaluate the correlation and consistency of each determination system.Results For the 4 domestic determination systems,the within-run CV were 17.6%-25.1%,0.8%-26.7%,7.8%-36.2% and 0.7%-20.2% for the standard products with different concentrations,respectively. The total CV were 15.9%-25.3%,1.0%-23.5%,7.7%-34.8% and 3.4%-18.9%,respectively. The linear correlation equations were Y=0.634X+0.973,Y=2.495X+0.010,Y=1.348X+0.896 and Y=2.510X-0.214,respectively. The S/CO value of the i2000SR system was 1.00-3.00 samples,and the determination consistency rate of the 4 domestic determination systems was 34.2%-55.2%. The determination consistency rates of the 4 domestic determination systems with S/CO values of 3.01-6.00 samples were 57.5%-80.0%. The determination consistency rates of the 4 domestic determination systems with S/CO values of 6.01-9.00 samples were >90%. The number of samples with negative results from the 4 domestic determination systems was 23（19.2%）,and the S/CO value $\bar{x}±3$s was 2.80±4.35. The number of samples with positive results from the 4 domestic determination systems was 71（59.1%）,and the S/CO value $\bar{x}±3$s was 5.13±7.84. The correlation coefficients（r）between 2 domestic reagents were 0.712 5,0.760 0,0.837 0,0.702 2,0.769 4 and 0.736 4,respectively. The Kappa values among the domestic reagents were 0.666 3,0.598 5,0.742 6,0.759 3,0.879 0 and 0.664 8,respectively. Conclusions For the gray zone samples（S/CO value of 1.00-9.41）,it is recommended that at least 2 reagents or highly specific reagents should be used for retesting. For low-concentration samples or cut-off samples,the possible inconsistencies between different determination systems should be fully considered,and a reasonable gray zone range should be formulated.

Key words: Hepatitis C virus, Antibody, Gray zone, Consistency