One of several viruses that can cause inflammation of the liver (hepatitis), and sometimes liver damage. Hepatitis B is very common in many parts of the world where it is often transmitted from mother to child at birth or in infancy. Most donors we identify have an association with these areas of the world and appear to have been infected since childhood or in early life. We do two tests for the virus; one looks for a marker called hepatitis B surface antigen, which is part of the ‘coat’ of the virus; and the second looks for the virus itself, targeting the virus nucleic acid. If we find surface antigen and/or the virus nucleic acid in a donor’s blood then further tests are performed to confirm the result. Many of the donors we identify have been infected with the virus for years and are completely well. Sometimes we find a donor with new (acute) hepatitis B infection. Most adults who get hepatitis B have a short illness and overcome the infection. Occasionally we get a positive result in our hepatitis B test because the donor has recently had an immunisation against hepatitis B and not because infection is present. In some circumstances, such as skin piercing, where there is extra risk of getting hepatitis B due to reusable needles, we carry out extra tests to see if you have ever had hepatitis B infection.
