The HBsAb Rapid Test is a rapid, direct binding test for the visual detection of antibodies to hepatitis B surface antigen (HBs) in serum/plasma. It is used as an aid in the diagnosis of hepatitis B infection. The HBsAb Rapid Test is based on the principle of sandwich immunoassay for determination of HBs in serum/plasma. Purified recombinant antigens are employed to identify HBs specifically. This onestep test is very sensitive and only takes 10-20 minutes. Test results are read visually without any instrument.
Hepatitis B virus (HBV) is a member of the Hepadnavirus family. The virus particle, (virion) consists of an outer lipid envelope and an icosahedral nucleocapsid core composed of protein. These virions are 42 nM in diameter and are sometimes referred to as "Dane particles". The nucleocapsid encloses the viral DNA and a DNA polymerase that has reverse transcriptase activity. The outer envelope contains embedded proteins that are involved in viral binding of, and entry into, susceptible cells. The virus is one of the smallest enveloped animal viruses, but pleomorphic forms exist, including filamentous and spherical bodies lacking a core. These particles are not infectious and are composed of the lipid and protein that forms part of the surface of the virion, which is called the surface antigen (HBsAg), and is produced in excess during the life cycle of the virus. The hepatitis B surface antigen (HBsAg) is most frequently used to screen for the presence of this infection. It is the first detectable viral antigen to appear during infection. However, early in an infection, this antigen may not be present and it may be undetectable later in the infection as it is being cleared by the host.