Signal to cut-off (S/CO) ratio and detection of HCV genotype 1 by real-time PCR one-step method: is there any direct relationship?

Abstract

Background: Polymerase chain reaction (PCR) methods play an essential role in providing data related to diagnosis, monitoring and treatment of hepatitis C virus (HCV) infection. EIA results are reported as "reactive" or "non reactive" and EIA S/CO ratio may also be reported as "high" or "low." This study aimed to evaluate the performance of a real-time RT-PCR and assess whether there is relationship between S/CO and PCR results. Study Design and Methods: Sera from blood donors were analyzed by Enzyme-Linked Immunosorbent Assay (ELISA) and RT-PCR assay to detect HCV infection. Results: The RT-PCR assay to genotypes 1a/b showed an acceptable linear response in serial dilutions. The samples were divided into two groups based on their serological results: group A -S/CO ratio < 3 (60 samples) and group B -S/CO ratio > 3 (41 samples). Viral loads were confi rmed positive in group B samples in 90%, and in group A samples were confi rmed positive in only 13% by RT-PCR. Conclusion: The methodology used was able to detect the presence of RNA-HCV genotype I in 90% of the samples serologically positive in group B. All negative samples were sent to search for other genotypes of HCV (genotypes 2-6) and were confi rmed as negative. These data suggests that these negative samples may have HCV RNA viral load below the detection limit of our test (310 IU/ mL), or a false positive result in serological test, or spontaneous viral clearance occurred.

Altered of apoptotic markers of both extrinsic and intrinsic pathways induced by hepatitis C virus infection in peripheral blood mononuclear cells

“…Amplification was performed using a 7500 Real-Time Sequence Detection System (SDS; ABI Prism 7500; Applied Biosystems, CA). RT-PCR product accumulation was monitored using a TaqMan probe 3940.…”

“…Dilutions of this standard were tested with a total of 24 replicates for each point dilution to determine the positive cut-off point or lower limit of detection. RT-PCR product accumulation was monitored using a TaqMan probe 3940.…”

Ortho VITROS enhanced chemiluminescence assay for detection of hepatitis C virus (HCV) antibodies: Determination of a borderline range

“…The increasingly sophisticated methods of diagnosing HCV infection have a direct impact on patient management and the use of more sensitive and specific assays is essential for an efficient diagnosis of HCV infection (Albertoni et al, 2010). Several seroprevalence studies have indicated that S/Co ratios could be used to accurately predict a positive status in conjunction with a confirmatory test Centers for Disease Control and Prevention, 2003;Dos Santos et al, 1999;Tobler et al, 2000).…”

“…Several seroprevalence studies have indicated that S/Co ratios could be used to accurately predict a positive status in conjunction with a confirmatory test Centers for Disease Control and Prevention, 2003;Dos Santos et al, 1999;Tobler et al, 2000). Although the majority of the seroprevalence studies reported were performed using the commercially available EIA test (Centers for Disease Control and Prevention, 2003;Dos Santos et al, 1999;Tobler et al, 2000;Albertoni et al, 2010), in the present study we utilized VITROS anti-HCV assay, whose performance was evaluated in some previous published studies. As reported by Ismail et al (2004), we also found, in the S/Co range of between 1 and 8, EIA negative/CIA positive samples.…”

“…The CDC has suggested selecting a S/Co ratio cut-off that identifies 95% of results as RIBA positive and below which 95% of samples are RIBA negative (Albertoni et al, 2010). At a CIA S/Co ratio cut-off of ≤ 8.0, 34 of 34 samples (100%) had negative RIBA results.…”