Immune Status
When requesting hepatitis B immune status, 'Hep. B I/S' or 'Hep. B immune', it is necessary to indicate whether you are looking for immunity following natural exposure to the virus, 'Hep. B I/S post exp.', or post vaccination immunity,
'Hep. B I/S post vacc.'. This is because there are at least two antibodies, core and surface, which can be tested for in hepatitis B. Both become elevated after natural exposure to the virus but only surface antibody rises after successful vaccination. Laboratories will test for Hepatitis B core antibody (HBVc Ab) if you request post exposure immune status or do not indicate on the request form that you are testing for post vaccination immunity. If you request the test for post vaccination immunity, the laboratory will test and report hepatitis B surface antibody (HBVs Ab).
There are two antigens which may be tested for in hepatitis B antigen carriage or chronic hepatitis B infection. They are hepatitis B surface antigen (HBVs Ag) which when present, may be accompanied by hepatitis B e antigen (HBVe Ag). Hepatitis B e antigen is associated with active viral replication and is also an indicator of greater infectivity in the patient. If you request 'Hep. B carriage' or 'Chr. Hep. B', the laboratory will perform and report a hepatitis surface antigen test. If this test is positive, the laboratory may perform a hepatitis e antigen test.
Hepatitis C
In comparison with hepatitis B, testing for hepatitis C presents no problems. At present there is only one test in the MBS. A positive hepatitis C antibody test (HCV Ab) may indicate acute infection, chronic infection, carriage or immunity. You simply request hepatitis C serology, ie., 'HEP. C'.
Hepatitis D
This is an uncommon form of hepatitis and occurs only in patients who are carriers of hepatitis B antigen. There is only one hepatitis D test available in the MBS, hepatitis D antibody test (HDV Ab). This test may be positive in both acute and chronic infection and the request is for hepatitis D antibody, ie., 'Hep. D'. Note that the item for this test is conditional on the patient also testing positive with a hepatitis B surface antigen test
Combination Testing
The remaining five items are simply combinations of some of the individual items where it is appropriate to investigate for more than one virus. In addition, there is a combined item for testing for syphilis with some of the serological markers.
Immune Status to hepatitis A and hepatitis B
On receipt of a request for determination of immune status to hepatitis A and hepatitis B, 'Hep. A, B I/S', the laboratory will perform a hepatitis A lgG antibody test (HAV IgG) and a hepatitis B core or surface antibody test (HBVc Ab or HBVs Ab). Chronic hepatitis B and hepatitis C
Testing may be carried out for both chronic hepatitis B and hepatitis C, ie., carriage of hepatitis B antigen and hepatitis C antibody positivity. Request 'chronic Hep. B, C' or 'Hep. B, C carriage' and the laboratory will perform a hepatitis B surface antigen test and a hepatitis C antibody test. If the hepatitis B surface antigen test is positive, the laboratory
may perform a hepatitis B e antigen test.
Acute hepatitis of uncertain etiology
There is provision for a request for acute hepatitis serology (Ac. Hep. A B C ) in a patient with abnormal liver function tests (LFT's), ie. 'currently elevated transaminase level'. Provided the laboratory has seen evidence of abnormal LFTs this request will result in the tests previously described for investigation of acute infection with hepatitis A, hepatitis B and hepatitis C being performed.
Syphilis and hepatitis B and/or hepatitis C
There is a combined item for testing for syphilis and carriage of hepatitis B and/or hepatitis C antibody. You should indicate which hepatitis serology is requested in addition to the syphilis test. That is 'Syphilis and Hep.B', 'Syphilis and Hep. C' or 'Syphilis and Hep.B and C'.
