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”.
Explanation of test results:

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.