A hepatitis B screening typically involves drawing blood from the patient which is then sent away to a lab for analysis. Three separate tests may be performed on the blood to diagnose whether an individual is infected. If the results of the tests are positive, additional blood may be required for a second set of tests which indicate the severity of the infection and whether permanent damage to the liver has occurred.
Hepatitis B is the inflammation of the liver through infection. This organ filters blood for the body, fights infections, and aids in the processing and digesting of nutrients. Permanent damage to the liver can cause it to fail and, in some cases, is fatal. The infection is spread through the sharing of bodily fluids or through childbirth from an infected mother to baby.
A blood test is the most commonly used method for conducting a hepatitis B screening. The blood may be drawn in a doctor's office or clinic and sent to a lab for a hepatitis B workup. Three standard tests are used to determine whether an individual currently has the infection, has had it previously, is immune to it, or has received a vaccine against it. These screenings search for hepatitis B antigens or antibodies in the blood, and doctors can use the results to determine the presence or lack of any infection. If this type of screening is performed in an early stage of the infection, hepatitis B can often be treated and cured before the patient has experienced any symptoms.
Depending on the results of the initial hepatitis B screening, additional tests may be required. The two least invasive means of further testing are blood tests. The first test looks for a different type of antigen in the blood which is produced by the infection. When high levels of this antigen, known as E antigen, are present, it indicates that an individual is extremely infectious and can easily pass it to anyone they come in contact with who is not immune. The second test searches for hepatitis B DNA levels, the results of which are used to determine the effectiveness of ongoing drug therapy.
When a hepatitis B screening returns positive results, and the individual is determined to be highly infectious, a liver biopsy may be necessary. This procedure involves the insertion of a thin needle directly into the liver through the skin. A small tissue sample is taken from the organ and analyzed. Hepatitis B tends to attack the liver directly, and a biopsy can help doctors identify the best course of treatment and whether the liver is in danger of failing.