Hepatitis B Surface Antigen (HBsAg) Screen LabCorp

Hepatitis B Surface Antigen (HBsAg) is used to screen for, detect, and assist in the diagnosis of acute and chronic hepatitis B Virus (HBV) infections. The test detects the protein that is present on the surface of the virus. This is the earliest routine indicator of acute hepatitis B and it frequently identifies infected patients prior to symptoms occurring. This is undetectable in the bloodstream during the recovery period. It is also indicative of those with chronic infections, including the 'HBV carrier' state. HBsAg positive blood donors are rejected. Notes: This test may exhibit interference when a sample is collected from a person who is consuming a supplement that contains high doses of Biotin (also termed as vitamin B7, B8, H, or coenzyme R), making it important to ask all patients about biotin supplementation who may be indicated for this test about. Patients should be cautioned to stop biotin consumption at least 72 hours prior to test collection. Limitations: Patients who present negative for HBsAg may still have type B viral hepatitis. Sometimes, there is a 'core window' stage when HBsAg becomes negative and the patient has not yet developed the antibody (anti-HBc). In occasions such as this, both tests for anti-HBc are usually positive and anti-HBc, IgM is the only specific marker for the diagnosis of acute infection with hepatitis B. In cases with strong clinical suspicion of viral hepatitis, serologic testing should not be limited to detecting HBsAg, but should include a battery of tests to evaluate the different stages of acute and convalescent hepatitis.