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[Quantitative antibody analysis: use for the diagnosis of hepatitis C virus chronic infection]
C Payan1, A Raimbert, I Fouchard-Hubert
1Laboratoire de bactériologie-virologie, (réseau hépatite 49), CHU Angers, 4, rue Larrey, 49033 Angers cedex. ChPayan@chu-angers.fr
Insights
Hepatitis C virus (HCV) chronic infection can be diagnosed using quantitative anti-HCV antibody testing, avoiding costly polymerase chain reaction (PCR) tests. A signal/cutoff ratio of 34 or higher strongly indicates chronic HCV infection.
Area of Science:
- Virology
- Immunology
- Medical Diagnostics
Background:
- Hepatitis C virus (HCV) infection affects a significant portion of the population, with chronic infection being common.
- Current diagnosis of chronic HCV infection relies on polymerase chain reaction (PCR) testing, which is laborious and expensive.
- Distinguishing chronic HCV infection from past infection or false positives solely through serology is desirable.
Purpose of the Study:
- To evaluate the correlation between anti-HCV antibody levels and PCR results for diagnosing chronic HCV infection.
- To determine if quantitative serological testing can replace PCR for HCV diagnosis in specific patient groups.
Main Methods:
- Analysis of 200 sera from 181 patients using the AxSYM HCV v.3.0 assay for anti-HCV antibody levels (s/co ratio).
- Correlation of s/co ratios with PCR results from the HCV Cobas Amplicor 2.0 assay.
- Statistical analysis to identify a predictive cutoff value for chronic infection.
Main Results:
- A significant difference in s/co ratios was observed between PCR-positive and PCR-negative patients (87.76 vs 10.13, p < 0.0001).
- An anti-HCV cutoff value of 34 s/co demonstrated 100% sensitivity and 93.3% specificity for predicting PCR results.
- Patients with s/co ≥ 34 had a 98.1% positive predictive value for chronic HCV infection.
Conclusions:
- Quantitative anti-HCV antibody testing can effectively diagnose chronic HCV infection in non-treated, non-HIV coinfected, non-renal transplant, and non-hemodialysis patients.
- The proposed cutoff value of 34 s/co can significantly reduce the need for PCR testing, simplifying diagnosis.
- This serological approach offers a cost-effective and efficient method for identifying chronic HCV infection.
Abstract:
Hepatitis C virus (HCV) infection has been estimated in 600,000 subjects in France, with about 80 % of chronic infection. In the latter, anti-HCV antibodies and viral RNA are found together in patients blood. Today, only the use of polymerase chain reaction (PCR) technology allows the diagnosis of HCV chronic infection, confirmed by a positive PCR. However, PCR is a laborious and cost effective method. The aim of this study was to distinguish HCV chronic infection to past-infection or false reactivity only using the serology testing. Therefore, we looked for a correlation between the results of PCR, using the HCV Cobas Amplicor 2.0 assay, and the level of anti-HCV antibodies, assessed by the AxSYM HCV v.3.0 and expressed in signal/cutoff (s/co) ratio. We found using a panel of 200 sera issued from 181 patients, a significant variation of s/co ratios between PCR positive and negative patients (respectively, 87.76 +/- 27.18 vs 10.13 +/- 13.68 s/co, p < 0.0001), only in non treated or previously treated patients, non HIV coinfected, non renal transplanted or haemodialysis patients. An anti-HCV cutoff value at 34 s/co allows a predictive PCR results with 100 % sensitivity and 93.3 % specificity. Thus, for patients having a s/co equal or over 34, a positive PCR was found in 98.1 % of cases, allowing the diagnosis of HCV chronic infection (positive predictive value). Conversely, in patients with less than 34, HCV chronic infection can be excluded in 100 % of cases (negative predictive value). In conclusion, in most cases, the use of anti-HCV quantitative analysis in the AxSYM HCV v.3.0 assay could avoid PCR testing and facilitate the diagnosis of HCV chronic infection.