From the Guidelines
Hepatitis C diagnosis and treatment planning require two crucial tests: HCV genotype testing and HCV RNA testing, with the most recent guidelines recommending HCV RNA quantitative assay and genotyping prior to antiviral treatment 1.
Diagnostic Tests for Hepatitis C
The diagnostic approach for Hepatitis C involves several steps, starting with the detection of anti-HCV antibodies, followed by HCV RNA testing for confirmatory diagnosis.
- HCV RNA testing is essential for diagnosing acute HCV infection, as HCV RNA appears before anti-HCV antibodies may be detectable 1.
- The HCV genotype test identifies which of the six major strains (genotypes 1-6) of the hepatitis C virus is present, crucial for determining the most effective treatment regimen.
- HCV RNA testing, or viral load testing, measures the amount of hepatitis C virus in the blood, confirming active infection and monitoring treatment response.
Importance of Genotyping and RNA Testing
Both genotyping and RNA testing are vital for treatment decisions, as they help determine the optimal therapeutic duration and dose of ribavirin, and whether the infection is active 1.
- Genotyping assays can be performed using direct sequence analysis, reverse hybridization, or restriction fragment mass polymorphism (RFMP), with most analyzing the 5’-untranslated region (UTR) and HCV core regions.
- RNA testing uses polymerase chain reaction (PCR) or transcription-mediated amplification (TMA) technology to detect viral genetic material in blood samples, with real-time PCR detecting minute quantities of HCV RNA and accurately quantifying HCV RNA levels.
Recommendations
The current recommendation is to perform HCV RNA quantitative assay and genotyping prior to antiviral treatment, as this information is crucial for determining the optimal treatment regimen and monitoring treatment response 1.
- HCV genotype and subtype can be determined via various methods, including direct sequence analysis, reverse hybridization, and genotype-specific real-time PCR.
- HCV RNA detection and quantification should be made by a sensitive assay, ideally a real-time PCR assay, with HCV RNA levels expressed in IU/ml.
From the FDA Drug Label
Plasma HCV RNA values were measured during the clinical trials using the COBAS TaqMan HCV test (version 2. 0), for use with the High Pure System. The diagnostic tests for Hepatitis C (HCV) genotype and Ribonucleic Acid (RNA) include:
- COBAS TaqMan HCV test (version 2. 0), which is used to measure plasma HCV RNA values. The COBAS TaqMan HCV test has a lower limit of quantification (LLOQ) of 25 IU per mL 2.
From the Research
Diagnostic Tests for Hepatitis C (HCV) Genotype and Ribonucleic Acid (RNA)
The diagnostic tests for HCV genotype and RNA include:
- Qualitative nucleic acid tests for confirmation of HCV infection and screening blood donations 3
- Quantitative HCV RNA testing for prognostic information regarding likelihood of treatment response and monitoring the antiviral response to treatment 3
- Genotype test results to provide important prognostic information related to therapeutic response and selecting treatment regimens 3
- Real-time RT-PCR assays, such as Cobas Ampliprep/Cobas TaqMan (CAP/CTM) and the Abbott real-time PCR test (ART), for quantitation of HCV RNA 4
- Molecular biology-based assays, including qualitative assays detecting HCV RNA, quantitative assays measuring HCV viral load, and tests analyzing the sequence of HCV genomes (genotyping assays) 5
Types of Diagnostic Tests
Some of the specific diagnostic tests for HCV genotype and RNA are:
- Roche TaqMan HCV analyte-specific reagent assay 6
- Abbott investigational use only RealTime HCV assay 6
- Bayer Versant HCV bDNA 3.0 assay 6
- COBAS Amplicor HCV Monitor 2.0 (CAM) 7
- COBAS TaqMan HCV Test for use with the High-Pure System (HPS/CTM) 7
- Versant Quantitative 3.0 (branched DNA [bDNA]) 7
Clinical Applications
These diagnostic tests have several clinical applications, including: