Hepatitis C RNA Quantitative Testing

The quantitative HCV RNA tests use either a process called polymerase chain reaction (PCR) or transcription-mediated amplification (TMA) or signal amplification (branched DNA). These are all "quantitative" techniques and will give an actual level of HCV RNA -- a measurement of the amount of hepatitis C virus in the blood. The result will be an exact number, such as "1,215,422 IU/L." Many people refer to the quantitative measurement as the hepatitis C "viral load."

There are 2 situations in which a quantitative test is useful:

The quantitative HCV RNA test is checked before a patient starts treatment.

For each patient, the result can be described as either a "high" viral load, which is usually >800,000 IU/L, or a "low" viral load, which is usually <800,000 IU/L. Knowing the viral load before starting treatment is useful because patients with "high" viral loads can have a difficult time getting the virus to become completely undetectable on treatment. Patients with "low" viral loads have a better chance of getting their virus to become completely undetectable on treatment.

The quantitative HCV RNA test is used to monitor a patient who is currently on treatment.

The response to treatment is considered good when the quantitative HCV RNA measurement drops and the virus eventually becomes completely undetectable.

• The viral load measurement does not tell us anything about the severity of a patient's liver disease or the degree of fibrosis (scarring). For that information, the patient would need a liver biopsy.
• It is not necessary to check the viral load repeatedly unless a patient is on treatment or is considering treatment.
• If a quantitative HCV RNA result is reported as "<615 IU/L," this means that the quantitative test cannot measure the hepatitis C virus. It may mean that there is no detectable HCV RNA at all, but it may mean that the level of virus is just too low for the test to pick it up. A qualitative test should then be performed to see if there is any detectable hepatitis C virus at all (see previous screen: "Hepatitis C RNA Qualitative Testing").
• If a quantitative HCV RNA results is "<615 IU/L" but the qualitative test is "detected" then the hepatitis C virus is present in the bloodstream, but at a very very low level, too low to be measured by a quantitative test.