A hepatitis B serology is a group of tests that can detect the presence of HBV and various antibodies in the serum of an individual with hepatitis B. Hepatitis B is a condition brought about by an infection with the hepatitis B virus (HBV). When the immune system of an individual detects the presence of this virus in the body, it produces several substances to protect the body. These are called antibodies and they are often present in the blood serum of the affected individual. The serum is the yellow part of the blood that can better be observed when a blood sample is left to stand for a few hours.
One of the tests in hepatitis B serology is done to detect the presence of the virus in an individual manifesting the symptoms of the disease. This test is called the hepatitis B surface antigen, or HBsAg. A positive HBsAg hepatitis B serology test can frequently indicate infection with the virus. Symptoms of hepatitis B infection include pain on the upper right abdomen, yellowing of the skin, itchiness, and appetite loss. The stool of an affected patient may also become gray-colored and his urine, tea-colored.
There are several antibodies in the serum of a hepatitis B patient that can be measured using several hepatitis B serology tests. These tests include the Anti-HBsAg, the anti-HBe, and the anti-HBc. The anti-HBsAg test measures the level of antibodies against the HBsAg of HBV. When it is present, it often means that the individual has been exposed to the virus and that he has already recovered from the infection. This test is also done after several doses of hepatitis B vaccination, to make sure that the body has enough protection against future infection.
High levels of anti-HBe often indicates that the presence of the virus is low. The anti-HBc hepatitis B serology can usually indicate infection even when the HBsAg and anti-HBsAg test are negative. Both tests may turn negative when the infection is in the window period.
The window period is the time when HBsAg has disappeared from the serum, and the antibodies against it have not yet appeared in the serum. Another hepatitis B serology test that can detect hepatitis B infection during the window period is the IgM anti-HBc test. IgM is a type of antibody present in the serum of patients with newly acquired infections.
Most patients usually recover from hepatitis B infection. Some patients, however, may have the disease longer than others. A hepatitis B serology test usually performed to monitor the treatment response of these patients is known as the HBV deoxyribonucleic acid (DNA) test.