[Evaluation of the patients with low levels of anti-HCV positivity].

Laboratory diagnosis of hepatitis C virus (HCV) infection is based on the detection of anti-HCV antibodies by enzyme immunoassay (EIA) or chemiluminescence immunoassay (CIA) techniques. However, a consensus related to the problem of low titer (Serum/Cut-off; S/C= 1.0) anti-HCV antibodies is still lacking. This study was aimed to evaluate the clinical status of the patients with low titer anti-HCV antibodies detected by third generation anti-HCV tests during january 2007-December 2007. Two hundred and fifteen sera with anti-HCV S/C values between 1-5, detected by a commercial test system (Vitros EC Immunodiagnostic System, 3rd generation anti-HCV test, Ortho-Clinical Diagnostics, USA) with a sensitivity of 100% and specificity of 99.7%, as indicated by the supplier, were included to the study. Alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels were determined by using chemiluminescence assay (Roche Diagnostics, Germany) and HCV-RNA was detected by real-time PCR (Flurion HCV QNP 2.1). Hundred and thirty six (63.3%) of the patients were female and 79 (36.7%) were male. The mean age of the patients was 50.2 +/- 18.9 years. In 18 (8.3%) patients ALT and/or AST levels were high and two of them were infected with hepatitis A while the remaining two with hepatitis B virus. HCV-RNA positivity (15.6 x 10(6); 4.3 x 10(5) and 2.6 x 10(3) IU/ml, respectively) was detected in three patients (1.4%) with S/C values of 3.69, 4.46 and 4.59, respectively. These three patients were older than 50 years, had high ALT levels and were chronic renal failure patients undergoing dialysis for at least one year. It was observed that after 4-6 weeks anti-HCV titers increased (S/C values were 15.1, 6.5 and 11.8, respectively) in the serum samples of these patients. The data obtained from this study emphasizes the problem of low titer positive anti-HCV results. It could be concluded that in case of low titer anti-HCV values, the result should be confirmed by RIBA, although its use is a matter of debate due to its low sensitivity, and HCV-RNA tests. Based on these data it seemed that changing the anti-HCV S/C ratio would not be a solution for the problem of low titer anti-HCV positive results.