What are the different types of blood tests used to detect hep C?
Hep C antibody tests
Doctors test for hep C by taking a sample of your blood and carrying out hep C antibody tests. Antibodies are your body’s reaction to a virus, not the virus itself. In the case of hep C, having antibodies does not protect you from catching hep C.
This test shows whether or not you have ever had hep C, but cannot tell if you still have it and have developed a chronic (long term) infection. This means that when antibodies are found, there is still a chance that you may have cleared the virus – one in four people (25%) clear the virus naturally. Hep C antibody tests are free if you take your Medicare card to a doctor who bulk bills.
It can take up to 12 weeks from the time you catch hep C until your body starts producing antibodies. This is called the ‘window period’; during this time that results may not be correct.
To find out if the hep C virus is still in your body, a different test is needed.
These are tests that look for the actual hep C virus (the PCR stands for polymerase chain reaction – the technology used to perform the test). The window period for the PCR test (the time between infection and when the virus can be found in the blood) is usually two weeks.
Three tests are performed using PCR technology and they provide different information about your hep C infection. The tests are available free through Medicare (although there is a limit as to how many tests per year will receive a rebate).
PCR viral detection test
The PCR viral detection test is used to check for the presence or absence of the hep C virus in the blood. This will inform whether you have cleared the virus naturally or successfully cleared the virus through treatment. The results are reported as detected (virus found) or not detected (virus not found).
PCR viral load test
This test measures the amount of virus in your blood. The result will be provided in a number. You can have high levels of virus in your blood and still feel well. It is often used to help people decide when to have hep C treatment.
PCR viral genotype test
PCR genotype tests can determine the genotype (strain) of hep C that you have. Knowing your genotype is important for treatment and will assist your doctor to determine which DAA medicines to prescribe for you.
Last review June 2018
For more information on hep C tests, you can contact the National Hepatitis Info Line on 1800 437 222.