Hepatitis C Virus (HCV) RNA, Quantitative Viral Load: Molecular Assay


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Subject: Hepatitis C Virus (HCV) RNA, Quantitative Viral Load: Molecular Assay

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  • The HCV viral load assay quantifies HCV RNA in the plasma of HCV-infected individuals. The HCV test is standardized against the first WHO International Standard for HCV RNA for nucleic acid amplification technology assays (NIBSC code 96/790).

  • Normal range: Not detected when the result is below the level of detection of the assay.


  • Methods

    • Branched DNA assay (bDNA; Siemens): A signal amplification technology that detects the presence of specific nucleic acids by measuring the signal generated by branched, labeled DNA probes; a reliable method that provides consistent results in the higher range of the assay.

    • Real-time PCR: Reverse transcription followed by amplification and quantification of the targeted DNA molecule; generally offers both a wider range of quantification and a lower limit of detection than the bDNA method.

  • Used in the management of HCV-infected individuals undergoing antiviral therapy.


  • PCR inhibitors in the specimen may lead to underestimation of viral quantitation or false-negative results in rare cases. However, current technologies include internal controls which if not amplified during the PCR, will not give a result rather than a false-negative result.