Detection of borderline and/or low positive anti-HCV results by enzyme immunoassay (EIA) leads to severe problems in routine laboratories and needs confirmation with nucleic acid amplification tests which can increase the cost. In EIA tests, if the ratio of sample to cut-off (S/Co) is ≥ 1, the sample is accepted as positive according to the manufacturers' instructions. Although over the last decade the application of S/Co values have also applied to HCV-RNA readings, the current study aims to determine whether the S/Co value is adequate and applicable for the anti-HCV EIA test, and to determine whether a correlation exists between HCV-RNA and HCV infections. A total of 658 cases (402 female, 256 male; mean age: 49.4 ± 17.0 years) who were found anti-HCV positive between January 2011-July 2013 were included in the study. Anti-HCV tests were performed by chemiluminescent EIA (Architect i2000SR, Abbott, USA and LiaisonXL Murex, DiaSorin, Italy) and HCV-RNA by real-time PCR (Cobas Ampliprep/Cobas TaqMan HCV, Roche, USA). The mean S/Co value of the cases was 7.3 ± 4.8 (range: 1.00-17.59) and mean HCV-RNA value was 2.3x105 ± 2.1x106 copies/ml. When the anti-HCV S/Co value of varying ranges was compared with HCV-RNA readings a particular trend was noted. In the anti-HCV S/Co values of 1.0-4.0; 4.1-7.0; 7.1-10.0; 10.1-13.0; 13.1-16.0 and ³16.1, HCV-RNA positivity rates were detected as 1.9%, 24.7%,37.1%, 46.7%, 56.4% and 75%, respectively. Statistical analysis indicated an intermediate positive correlation (r= 0.454) between anti-HCV ve HCV-RNA readings (p= 0.000). An adequate S/Co value was accepted as 5.0 based on the ROC analysis, and this value gave a performance confidence level of 95.6% when determining whether a patient is HCV positive. Based on the data of this study it became evident that further EIA testing is not required if the S/Co value is ≥ 5.0, however if the S/Co value is less than 5.0, then further clinical analysis and revaluation of the patient is required.