Hepatitis C Virus (HCV)
Hepatitis C virus (HCV) testing is used to assess several aspects related to hepatitis C infection:
- Diagnosis of Hepatitis C Infection: HCV testing is the primary diagnostic test for hepatitis C infection. The presence of HCV RNA or antibodies to HCV in the blood indicates active or past HCV infection, respectively. Diagnosis of hepatitis C involves testing for HCV RNA to confirm active infection, followed by testing for antibodies to HCV to differentiate between acute and chronic infection.
- Screening for Hepatitis C Infection: HCV testing is used for screening individuals who may be at risk of HCV infection, such as those with a history of injection drug use, recipients of blood transfusions or organ transplants before 1992, individuals born to HCV-infected mothers, healthcare workers, and individuals with liver disease or abnormal liver function tests.
- Identification of HCV Carriers: HCV testing helps identify individuals who are carriers of HCV, meaning they have chronic HCV infection and can potentially transmit the virus to others. Chronic HCV infection is diagnosed if HCV RNA persists in the blood for six months or longer. HCV carriers require monitoring for liver disease progression and consideration of antiviral therapy to suppress HCV replication.
- Assessment of Disease Severity: HCV testing, particularly quantitative HCV RNA testing, is used to assess the severity of liver disease and monitor disease progression in individuals with chronic HCV infection. Higher levels of HCV RNA are associated with more severe liver disease and may indicate the need for more intensive monitoring and treatment.
- Selection of Antiviral Therapy: HCV testing, including genotyping and resistance testing, is used to guide the selection of antiviral therapy for individuals with chronic HCV infection. Genotyping helps determine the HCV genotype, which influences treatment duration and choice of direct-acting antiviral (DAA) medications. Resistance testing may be performed to identify HCV variants resistant to specific antiviral drugs.
- Monitoring Response to Treatment: HCV testing is used to monitor the virological response to antiviral therapy in individuals undergoing treatment for chronic HCV infection. Periodic testing for HCV RNA during and after treatment helps assess treatment efficacy, determine the need for treatment modification, and confirm sustained virological response (SVR), defined as undetectable HCV RNA six months after completing treatment.