the usefulness of anti-hcv signal to cut-off ratio in predicting viremia in anti-hcv in patients with hepatitis c virus infection

background: hepatitis c virus (hcv) infection is diagnosed by antibody and rna based methods. patients with anti-hcv sample rate/cutoff rate (s/co) ratios 1 are reported as anti-hcv positive. rna based methods are introduced to confirm positivity in seropositive samples. objectives: the current study aimed to assess relationship between s/co rates and hcv-rna levels in the laboratory to identify hcv viremia in patients with a positive anti-hcv. patients and methods: all serum samples were assayed for anti-hcv by elisa method. a total of 265 anti-hcv positive patients were tested for hcv-rna testing by quantitative method using artus hcv rg real-time polymerase chain reaction (rt- pcr) kit. statistical analysis was done by spss version 16. results: of the 265 patients with hcv infection, 204 (77%) were male and the mean age was 43.53 ± 13.17 years, ranging 1 - 81 years. no correlation was found between s/co ratios and hcv-rna levels. there was significant difference in s/co ratio between viremic and non-viremic subjects. the sensitivity, specificity, negative predictive value, and positive predictive value were 100%, 81.4%, 100%, and 77.2%, respectively in the s/co ratio of 2.7. conclusions: the present study indicated that anti-hcv s/co ratio is useful to predict non-viremic patients. a cut-off value of 2.7 can determine the usefulness of hcv-rna testing. patients with s/co 2.7 are not viremic; therefore, hcv-rna testing is not recommended. it is suggested that laboratories report s/co ratio along with anti-hcv results to manage hcv infection better, especially in countries that quantitative hcv testing is expensive or not available.