Monday, September 12, 2011

Laboratory Diagnosis of Hepatitis C Virus Infection.

Due to the lack of typical symptoms diagnosis of acute hepatitis C is rarely established. Because HCV antibodies may develop later during the course of hepatitis C diagnosis of acute infection is based on the detection of HCV-RNA together with a history of contact to a HCV positive source, a course of increased liver enzymes from previous normal levels and/or the absence of HCV antibodies (Jaeckel et al., 2001 and Gerlach et al., 2003).
After screening for chronic HCV infection by anti HCV antibody testing past or ongoing hepatitis C in anti-HCV positive patients is determined on the basis of HCV core antigen and HCV-RNA. During selection of patients for screening of hepatitis C one has to be aware that typical symptoms of chronic liver damage and even elevated liver enzymes are often not present in patients with HCV infection. This together with a relative slow progression of the disease has led to the fact that at present only in a minority of patients diagnosis of CHC is established. After proof of CHC the need for antiviral therapy has to be assigned on the basis of the level of liver enzymes, histological grading and staging of liver damage, extra hepatic manifestations of the disease, as well as the social and personal situation of the patient (National Institutes of Health, 2002).
For management of treatment, determination of HCV genotype provides important information about the chance of sustained virologic response and the projected duration of interferon alfa-based antiviral therapy (Hadziyannis et al., 2004 and Zeuzem et al., 2004).
The key parameter for assessment of antiviral response during therapy is HCV-RNA. Precise and reliable quantification and highly sensitive detection of HCV-RNA before, during and after interferon alfa based antiviral therapy is critical for determination of virologic response and premature discontinuation of therapy in virologic-non-responders (Poynard et al., 2000; Fried et al., 2002; Berg et al., 2003 and Davis et al., 2003).

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