The qualitative test detects the presence or absence of HCV RNA and is reported as either detected (positive) or not detected (negative). This is useful in a patient who has a positive RIBA test to confirm active infection.
The quantitative test measures (using PCR) the number of copies of HCV RNA (the genetic material for HCV) in the blood, also known as the "viral load." This number is used to monitor a patient's response to treatment for HCV. For example, doctors will measure your viral load before and during treatment and compare the results. You want to have a significant decrease in viral load (specifically a "2 log" decrease) by the first 12 weeks of treatment. A decrease less than this may mean you're not responding to therapy.
Who Should Get a HCR RNA Test?Current guidelines suggest that you should get a HCV RNA test if you:
- Have a positive hepatitis C screening test (the HCV RNA test will detect the presence or absence of active virus in the blood)
- Will be starting treatment for chronic hepatitis C
- Have unexplained liver disease and a compromised immune system (or suspected of having acute hepatitis C) but have a negative hepatitis C antibody test
Dienstag, JL. Acute Viral Hepatitis. In: AS Fauci, E Braunwald, DL Kasper, SL Hauser, DL Longo, JL Jameson, J Loscaizo (eds), Harrison’s Principles of Internal Medicine, 17e. New York, McGraw-Hill, 2008.
Terrault NA, Chopra, S. Screening For and Diagnostic Approach to Hepatitis C Virus Infection. UpToDate. Waltham, MA. Accessed: October 21, 2009.
United States Department of Veterans Affairs. Hepatitis C RNA Qualitative Testing. Accessed October 21, 2009.
United States Department of Veterans Affairs. Hepatitis C RNA Quantitative Testing. Accessed October 21, 2009.