How can HBsAg become negative

HBV s-AG (HBSAG)

The detection of the s-surface protein (s - ["surface"] - antigen [AG]) of the hepatitis B virus (HBV) means that there is an infection with this virus.

A number of tests are used for laboratory diagnostic clarification of the HBV infection or for examination with regard to existing HBV vaccination protection. The following substances can be determined in the blood:

  • HBV s antigen (surface protein of HBV),
  • Antibodies against the HBV s antigen,
  • Antibodies against the HBV c antigen ("core" antigen - a virus protein that envelops the genetic material of the virus; this antigen itself cannot be detected in the blood),
  • IgM antibodies against the HBV c antigen,
  • HBV e-antigen (this virus protein is partly identical to the c-antigen and is released into the blood),
  • Antibodies against the HBV e antigen,
  • HBV genetic material (DNA - deoxyribonucleic acid).
Hepatitis B is a disease that results from infection with the hepatitis B virus. This leads to inflammation of the liver tissue (hepatitis). Jaundice (jaundice) can occur with this condition. The acute illness lasts about two weeks to three months. In about half of the cases the disease proceeds without symptoms. Severe disease courses occur in about one percent of the cases.

The most important complication of hepatitis B is the transition to chronic liver inflammation (in five to 90 percent of cases, depending on age). The rate of chronicity is highest in newborns and decreases with age. In a quarter of all chronic hepatitis B cases, after many years there is a scarring “shrunken liver” (cirrhosis of the liver), which in turn represents a risk factor for the development of a malignant liver cell tumor (hepatocellular carcinoma).

Infection with the hepatitis B virus can occur in a number of ways. The most common causes of infection are

  • Transfusion of blood or administration of blood products (plasma, coagulation factors, etc.) - in Austria the risk of transmission of viral hepatitis in this way is extremely low,
  • Injury with contaminated needles or sharp objects (e.g. razor blades, tattoo tools),
  • Sexual intercourse (hepatitis B is often transmitted this way),
  • Infection of the newborn at birth from an HBV infected mother.
The following options are available to prevent hepatitis B:

  • Vaccination;
  • Never use hypodermic needles together (so-called “needle sharing” among drug addicts); Do not use nail scissors, razor blades or toothbrushes together with a person known or suspected to be infected with hepatitis B;
  • Passive immunization: Administration of hepatitis B immunoglobulin after needlestick injuries or in newborns of a mother with chronic hepatitis B (HBV s antigen positive) immediately after birth.