Clinical diagnostic services
Hepatitis C (HCV)
Viral Load Testing
and Genotyping
Personalised care for the clinical management of HCV
What is HCV viral load testing and HCV genotyping?
HCV viral load refers to the level of viral RNA molecules found in each mL of blood. HCV viral load testing is intended for use in conjunction with clinical presentation and other laboratory markers of disease progression for the clinical management of HCV infected patients. HCV viral load testing is not intended to be used as a screening method for HCV or as a diagnostic test to confirm the presence of HCV infection.
HCV is a heterogeneous virus with 6 distinct genotypes. Consensus guidelines for HCV management in Europe and the USA define that dose and course of therapy should be dictated specifically by the genotype present. HCV genotyping assesses signature sequence motifs present in defined parts of the viral genome. This is usually based on the 5’ non-coding (NC) region of HCV genome which is a highly conserved part of the virus and can accurately discriminate between specific genotypes.
How does the testing service work?
What is included in the report?
Results of this test will be sent to the GP or clinical specialist. HCV viral load is reported as the number of HCV RNA molecules in each millilitre of blood plasma (reported as ‘copies/mL’). The HCV genotyping report will indicate the specific HCV genotype and subtype from the patient sample.
How often should Viral Load and HCV genotype
be tested?
- Baseline measurement – HCV viral load and genotype should be determined before treatment, as it determines the indication, the duration of treatment, the dose of treatments and the virological monitoring procedure.
- Viral load measurement after starting therapy – HCV RNA monitoring during therapy is used to tailor treatment duration and to assess the efficacy of therapy.
- HCV viral load testing is used to assess the end-of treatment and most importantly the sustained virological response, i.e. the endpoint of therapy.
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How do patients benefit?
The HCV viral load test can be used to assess patient prognosis by measuring the baseline HCV RNA level and to monitor the benefit and efficacy of therapy by measuring the decrease in the level of the virus in the blood. It can also alert the physician to the appearance of drug resistance if plasma HCV RNA levels start to increase during the course of treatment.
Viral load is an important sign of how well the goal of therapy is being met; keeping the virus under control or suppressed for as long as possible.
HCV genotyping will determine the type of the HCV virus which will then be used for therapeutic decision making. If resistance does appear then genotyping is a typical method to analyse the nature of the resistance.
From receipt of the patient sample at our laboratory, a fully interpreted report will be sent to the clinician within 4 working days for the HCV viral load test and 10 working days for HCV genotyping.
