Hepatitis B virus tests are blood tests that check for antigens. Antigens are a type of protein that can be found in the hepatitis B virus. When the hepatitis B virus (HBV, or hep B) is present in our body, our immune system produces antibodies in response to these antigens as it tries to fight HBV. The hep B virus is made of three types of antigens—known as surface, core, and E antigens—so blood tests can help us understand if we have hep B currently, have cleared the infection or if we have been vaccinated,
Hepatitis B surface antigen test
The hep B surface antigen test detects current HBV infection by detecting antigens of the virus itself in our blood. Antigens are detectable 4-10 weeks after exposure to the virus. A positive HBV surface antigen test means the virus can be passed to others.
If your body successfully clears the infection on its on, as happens in acute hep B, this test result will be negative.
If you continue to have a positive hep B surface antigen test after 6 months, this is what is known as chronic hep B
Hepatitis B core antibody test
The hep B core antibody test can tell us if a person has ever been infected with the hepatitis B virus, even if they have cleared that infection (it has gone away).
The hep B core antibody test can not tell us if we are currently infected, have cleared the virus or if we are immune to the virus—only that we have had a past hep B infection.
Hepatitis B surface antibody test
The hepatitis B surface antibody test can tell us if we are immune to the hepatitis B virus. We may become immune to HBV if we have:
- Cleared the hep B virus after infection, or
- Have been vaccinated against the hepatitis B virus
If you’re not sure you’ve been vaccinated for hep B, the hepatitis B surface antibody blood test can tell you—but it’s safe to be vaccinated again if you can’t get tested or if you’ve previously had a hepatitis B infection.
School-based vaccination programs for hep B began in 1987 in Canada [2], but the schedule children are vaccinated varies depending on which province they live in. Adults can also be vaccinated for hep B if they didn’t receive the hep B vaccine as children. Immunize Canada also has tips for locating old vaccine records if you’d like to know if you’ve been vaccinated.
Learn about hepatitis B vaccination in BC (Health Link BC).
Who should be tested for hepatitis B?
The Public Health Agency of Canada considers the following to be associated with higher risk of hepatitis B infection. A person should be screened for hepatitis B if [3]:
- They were born in a region that has a high rate of hepatitis B prevalence (greater than 2% [4]]
- The parent who gave birth to them has hepatitis B
- They have a family history of hepatitis B or hepatoma (a liver cancer)
- They may have been exposed before age 7 (such as if the child was born in or visited a country with high rates of hep B)
- They have traveled to or lived in an area with high hep B rates without having been vaccinated for HBV.
- They live or are in sexual contact with someone positive for hepatitis B
- They have unprotected sex, or sexual contact with multiple partners)
- They use substances and have ever shared drug use equipment
- They have shared or used potentially contaminated equipment for body modification, piercing, tattooing, or received any alternative health practices that may break the skin (ie. Acupuncture)
- They have received or were exposed to blood or blood products in regions with high rates of hep B where blood products aren’t screened
- They received a blood transfusion in Canada prior to 1970
- They have had a medical procedure done in Canada prior to 1970
- They have ever shared medical devices (such as blood glucose meters/lancets) or may have used a contaminated device
- They work in an occupation with greater potential exposure to blood or body fluids.
- They have been incarcerated
- They live in an institution (ie. Personal care home, especially those providing care to people with intellectual/developmental disability)
Routine screening for hepatitis B in Canada is not typically done, but is suggested in [3]:
- Pregnancy
- People with HIV or HCV
- People who are immunocompromised due to a medical condition or medication
- Planning medical treatment with immunosuppressant or immunoregulatory medications, as they may increase risk of liver-related illness or reactivation of hepatitis B.)
Some regions with higher rates of hep B include Asia, the Pacific Islands, Africa and Eastern Europe. The University of Alberta provides a list of countries that are highly endemic—or have a higher prevalence of—hepatitis B.