hepatitis B serology(redirected from Surface Antigen)
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hepatitis B serologyHepatitis B serological markers Lab medicine A generic term referring to hepatitis B antigens and antibodies to these antigens
Hepatitis B serology
Core antigen The HBc particle that contains double-stranded DNA and DNA polymerase, and is associated with the HBe antigen; HBc is not directly detected by currently-used assays; its presence indicates persistently replicating hepatitis B virus
Core antibody A long-term serologic marker for HBV, with 2 antibodies
• IgM HBcAb A marker of acute infection, which rises early–within 2-4 weeks of HBV infection and slowly disappears; ↓ levels of IgM HBcAb indicate resolving infection; IgM HBcAb is the best serologic marker for acute HBV infection
• IgG HBcAb A 'convalescent' antibody that indicates prior HBV infection; it rises 4-6 months after infection and persists for life, especially in those with active liver disease; partially protective anti-HBc antibody levels can be induced by recombinant vaccination, but are short-lived
e antigen An antigen that rises and falls parallel to HBsAg, and derives from the proteolytic cleavage of the nucleocapsid; its presence implies a carrier state
e antibody Anti-HBe An antibody that rises as HBe falls, appearing in convalescent Pts, persisting for up to several years after resolution of hepatitis
Surface antigen HBsAg The first marker to appear after HBV infection, preceding clinical disease by weeks, peaking with the onset of symptoms and disappearing six months post-infection; as long as HBsAg is positive, the Pt is considered infectious and must follow prescribed sanitary procedures to avoid infecting others; if the hepatitis does not resolve, HBsAg persists and can be detected for many years or life.
Antibody to surface antigen HBsAb, anti-HBs, antibody to surface antigen HBsAb begins to rise as the HBsAg falls; it is detectable 8-10 weeks post infection, is regarded as being protective against re-infection, and persists for life; HBsAb is formed after using the HBV vaccine, and is not present in the chronic phase of the disease.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.