The viral load test is useful in several areas:
Diagnosis: The test can detect the presence of HCV a few days after infection with HCV, before the antibody test is positive.
• Confirmation of Chronic Infection: As noted above, up to 15% of people infected with HCV eradicate the infection. This process could take up to 6 months. However, antibody testing on these people will still give a positive result. A viral load test is used to determine if they have chronic infection.
• To predict treatment success: People with a viral load less than 400,000 generally get better results.
• Therapy management: The test determines if the treatment is controlling the virus. There are several viral load measurements for treatment response. These are described below. HCV viral load cannot be used in the same way as HIV viral load (see fact sheet 125). It is not a good indicator of the severity of HCV, or how fast the virus will progress. It is also more complicated to use it to evaluate the response to treatment. However, lower viral loads are associated with a better response to HCV therapy. In addition, higher viral loads are linked to an increased risk of HCV transmission, at least from pregnant women to their newborns.