Hepatitis B is diagnosed by a blood test that shows a positive reaction to hepatitis B surface antigen (the outer surface of the hepatitis B virus that triggers a response from your immune system). A positive result means that your body is making antibodies to try and fight the hepatitis B virus.

Your GP may also request a liver function test. This is a blood test that measures certain enzymes and proteins in your bloodstream, which indicates whether your liver is damaged. These will often show raised levels if you are infected with the hepatitis B virus.

Antibodies

Antibodies and immunoglobins are proteins in the blood. They are produced by the immune system to fight against bacteria, viruses and disease.

Biopsy

A biopsy is a test that involves taking a small sample of tissue from the body so it can be examined.

Enzymes

Enzymes are proteins that speed-up and control chemical reactions, such as digestion, in the body.

Inflammation

Inflammation is the body's response to infection, irritation or injury, which causes redness, swelling, pain and sometimes a feeling of heat in the affected area.