“ The HCV RNA PCR test is a blood test. A lab technician looks for the genetic material of the HCV virus, or its ribonucleic acid (RNA). They use a process called a polymerase chain reaction (PCR).
The results of the HCV RNA PCR test help a doctor recommend different ways of reducing the viral load. The viral load indicates how many HCV viral particles are in the blood.
If a doctor suspects that a person has HCV, they will recommend this test early on in the diagnostic process, even if it is not the first test they carry out.
The test can detect the presence of the virus itself, rather than the antibodies that the body creates in response to the virus.
This means that a person does not have to wait until symptoms of the infection develop for a diagnosis.
It can take an average of 6–8 weeks for antibodies to become detectable after an HCV infection begins. However, a doctor can identify the virus itself after about 1-2 weeks by using PCR or another means of direct virus detection.”
“How it works
Doctors use the HCV RNA PCR in one of two ways:
a qualitative test determines whether or not the virus is present
a quantitative test measures the amount of HCV in the bloodstream
There are slight differences in the process for each form of the test.
A doctor may be uncertain whether a person has HCV or not. They can request this test to detect the virus in the bloodstream.
The qualitative test only detects the presence of the virus. It does not determine the number of HCV viral particles in the body.
A doctor will usually recommend an HCV RNA PCR test after a positive HCV antibody test. This test will show if the body is making the antibodies that fight HCV.
While a test that identifies antibodies is usually a good indication of HCV infection, false positives are possible.
A positive test might occur when a person has had a previous HCV infection. This may mean that a person still has antibodies, but the body has already cleared the infection. This happens in about 15–25% of tests.
The virus is more likely to clear in people whose symptoms develop in the early phase of the infection. This is why doctors routinely follow up an HCV antibody test with an HCV RNA PCR test to confirm the diagnosis.
In some cases, doctors may also recommend a third test to confirm the presence of hepatitis C. Doctors call this the transcription-mediated amplification (TMA) test.
The TMA test is not necessary in many cases where an HCV RNA PCR test shows strong enough evidence of an HCV infection.
The quantitative HCV RNA PCR test indicates the number of viral copies of HCV in the blood. It works by detecting how much genetic material is present in a small amount of blood.
For many people, the quantitative test has replaced the qualitative test. This is because knowing and understanding the viral load is a crucial step in the treatment process for people with HCV.
The doctor calculates the measurements to match the standard reading, which is the number of international units per milliliter (IU/ml).
Doctors often use a quantitative test when establishing the diagnosis and to monitor the amount of HCV in the bloodstream during treatment. This lets them know how well the body is responding to the treatment, as well as helping them decide on any necessary changes in treatment.“
Why the rush to know? It takes weeks to get started on treatment having a hep c infection is not a medical emergency
The HCV antibody test is normally performed first. This test looks for the presence of hep c antibodies in the blood. Antibodies are made by an infected person in response to an infection. It can take as long as 12 to in some cases (immune compromised patient) up to 24 weeks for enough antibodies to develop to detectable levels.
The HCV RNA by PCR test looks for the presence of the hep c virus itself. This test can detect the virus in a few weeks post exposure.
Have you had a concerning blood to blood exposure? Hep c is a blood borne virus and is not transmitted by casual contact.
Most common methods of transmission are sharing of IV drug needles with other drug users or engaging in rough sex practices where blood exposure could occur. Also sexual relations outside of a long term monogamous relationship ie multiple sexual partners without using protection like condoms.
Or if you are a health care worker and experience an accidental needle stick involving a patient with known hepatitis C infection.