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Analysis for hepatitis B: HBSAg in the blood
Medical expert of the article
HB s Ag in serum is normal.
Detection of the surface antigen (HBsAg) of hepatitis B virus in the serum confirms acute or chronic infection with HBV virus.
In acute disease, HB s Ag is detected in the blood serum in the last 1-2 weeks of the incubation period and in the first 2-3 weeks of the period of clinical manifestations. Circulation of HB s Ag in the blood can be limited to a few days, so we should strive for early primary examination of patients. The frequency of detection of HB s Ag depends on the sensitivity of the test method used. The ELISA method allows to detect HB s Ag in more than 90% of patients. Almost 5% of patients with the most sensitive methods of investigation do not reveal HB s of Ag, in such cases, the etiology of viral hepatitis is confirmed by the presence of anti-HB- c of IgM. Concentration of HB s Ag in serum for all forms of viral hepatitis B gravity height of the disease has a significant range of variation, however, there is some regularity in the acute stage is an inverse relationship between the concentration of HB s Ag in the serum and the severity of the disease. A high concentration of HB s Ag is often observed in mild and moderate forms of the disease. In severe and malignant forms, the concentration of HB s Ag in the blood is often low, and in 20% of patients with severe form and in 30% of malignant antigens in the blood can not be detected. Appearance against this background in patients with AT to HB s Ag is regarded as an unfavorable prognostic sign, it is determined in malignant forms (fulminant) of hepatitis B virus.
In the acute course of viral hepatitis B, the concentration of HB s Ag in the blood gradually decreases until the antigen disappears completely. HB s Ag disappears in most patients within 3 months of the onset of acute infection. Reduction of HB s Ag concentration by more than 50% by the end of the 3rd week of an acute period, as a rule, indicates a close end to the infectious process. Usually, in patients with a high concentration of HB s Ag at the height of the disease, it is found in the blood for several months. In patients with a low concentration of HB s Ag, it disappears much earlier (sometimes several days after the onset of the disease). In general, the detection period of HB s Ag ranges from several days to 4-5 months. The maximum term of detection HB s of Ag with a smooth flow of acute viral hepatitis B is not more than 6 months from the onset of the disease.
HB s Ag can be detected in practically healthy people, usually with preventive or accidental research. In such cases, other markers of viral hepatitis B-anti-HB c IgM, anti-HB c, anti-HB e, are studied, the functional state of the liver is studied. At negative results of repeated measurements needed to HB s of Ag. If HB s Ag is detected during repeated studies of blood for 3 months or more , this person is referred to as chronic surface antigen carriers. Bearing HB s Ag - a fairly common phenomenon. There are more than 300 million vehicles, in our country - about 10 million Termination circulation HB. S of Ag followed by seroconversion always indicative of the body rehabilitation.
The blood test for the presence of HB s Ag is carried out for the following purposes:
- Diagnosis of acute viral hepatitis B:
- incubation period;
- acute period of the disease;
- early stage of convalescence.
- diagnosis of chronic carrier of the virus of hepatitis B;
- with the following diseases:
- persistent chronic hepatitis;
- cirrhosis of the liver;
- screening, identification of patients at risk:
- patients with frequent blood transfusions;
- patients with chronic renal insufficiency;
- patients with multiple hemodialysis;
- patients with immunodeficiency conditions, including those with HIV infection.