More information on hepatitis E tests.
Hepatitis E antibody test
Your immune system is always on the lookout for things in your body that should not be there. When it spots something, like a new virus, it has lots of ways to deal with it.
One of the things your immune system does is start to make lots of antibodies. These antibodies are proteins. They are specially selected because they stick to parts of the virus.
Once the antibodies have stuck, they act as a signal to other parts of your immune system. Telling them to come and get rid of the virus.
The antibody test looks for antibodies against hepatitis E in your blood. It can take 2 to 6 weeks for your body to start making enough antibodies for the test to work. So if you have only just picked up the virus the test might be negative.
After you have got rid of the virus, your immune system will start to make a slightly different type of antibody. These antibodies stay in your blood to stop you getting hepatitis E again. Because they are a different type, they will not be picked up on the antibody test used to diagnose hepatitis E.
So the hepatitis E antibody test will only be positive if you have the virus at the time of the test.
If you are immunosuppressed, you might not make antibodies. So you should have an RNA test instead.
Hepatitis E RNA test (might be called a PCR test)
The hepatitis E virus contains genetic material called RNA. This is the instructions for making more copies of the virus.
The RNA test looks for this RNA in your blood. The RNA can also be found in the poo of someone with hepatitis E.
You might also hear this called a PCR test because a machine called a PCR machine is used to carry out the test.
RNA tests can pick up the virus sooner than an antibody test. The RNA test will start to work just before you get symptoms. But for most people it will only work for about 3 weeks after symptoms start. This is because your body is getting rid of the virus, so there is less of its RNA in your blood.
For people who develop long term (chronic) hepatitis E, the RNA test can carry on working for longer. If you have chronic hepatitis E you might have regular RNA tests to see how your treatment is working.