To our knowledge, this is the first study on the correlation between VIDAS and Architect assays. In conclusion, the VIDAS Anti-HCV assay showed excellent agreement with the Architect Anti-HCV Assay and Roche COBAS TaqMan HCV PCR Assay. Armonk, NY, USA) or in MedCalc (MedCalc Software, Ostend, Belgium). RESULTS 1. PK14105 Comparison of the VIDAS anti-HCV assay with the results of Human PK14105 Serum Bank The 100 HCV-positive samples were all test-positive (TV 22.561.24) and 997 of 1 1,002 HCV-negative samples were test-negative according to the VIDAS assay. Five samples showed discrepant results between the VIDAS assay and HSB data. These five all tested negative in the Architect assay and COBAS PCR, but were test-positive according to the VIDAS assay. Therefore, the positive and negative agreement rates of the VIDAS assay were 100% (95% confidence interval [CI]: 96.4-100%) and 99.5% (95% CI: 98.8-99.8%), respectively (Table 1). Total agreement rate of the results between the VIDAS assay and HSB was 99.5%, and the coefficient was 0.973 (95% CI: 0.950-0.997). Table 1 Comparison of the results of the VIDAS anti-HCV assay with those of the Human Serum Bank and Core, NS4A, and NS4B peptides as antigens. One of the five discrepant samples in our study showed very weak reactivity in the VIDAS assay (TV 1.05) and Core 2+ and NS3-2 2+ reactivity on MP blot, indicating a true positive result. We retested the Architect Anti-HCV Assay on this sample and obtained a positive result (S/CO 1.3), which was different from the original Architect result. We analyzed the sample using additional methods: Elecsys Anti-HCV II (Roche Diagnostics, Mannheim, Germany) and ADVIA Centaur HCV (Siemens Healthcare Diagnostics, Marburg, Germany) assays, both of which Rabbit polyclonal to AADAC yielded a PK14105 negative result. Other two discrepant samples (VIDAS TVs 1.30 and 6.23) showed negative results on the MP blot. The three discrepant results described above may be caused by the differences in antigens or epitopes between the assays rather than the random error. The other two samples (VIDAS TVs 1.91 and 2.42) showed only NS4 2+ reactivity and were interpreted as indeterminate on the MP blot. Indeterminate results of the immunoblot assay are defined as any single band having 1+ or greater reactivity (except 2+ or greater reactivity for the Core band only, which indicates a positive result in the MP Diagnostics HCV Blot assay) and can be seen in a cleared HCV infection or during early seroconversion and may be due to nonspecific reactivity . Isolated Core or NS3 reactivity means a higher probability of true presence of anti-HCV antibodies and may be the sign of acute or chronic HCV infection in case of a high S/CO ratio and strong reactivity on the immunoblot assay; in contrast, isolated NS4 reactivity is considered a false positive result (does not indicate HCV infection) [11,12,13]. Because the two samples that showed indeterminate results in our study were weakly test-positive according to VIDAS and showed NS4 2+ reactivity on the MP blot, these results likely PK14105 indicate nonspecific (false) reactions. According to the United States Centers for Disease Control and Prevention (CDC) guidelines for laboratory testing PK14105 and result reporting on antibodies to hepatitis C virus [4,14,15], an anti-HCV antibody assay with high sensitivity should be used for screening tests, and test-positive results should be verified by a more specific serologic test or PCR test, particularly in populations with low HCV prevalence. On the other hand, these recommendations have not been followed by the majority of clinical laboratories for multiple reasons. Therefore, the US.