Hepatitis B Surface Antigen
Definition - What does Hepatitis B Surface Antigen mean?
A hepatitis B surface antigen (HBcAg) is a protein molecule which is present on the outer surface of the hepatitis B virus. The presence of this antigen in the blood is an indication that an individual has been infected with the hepatitis B virus (HBV).
It is these surface antigens which trigger the body's immune response to a hepatitis B infection. A blood test for the hepatitis B surface antigen may detect the presence of the virus prior to an individual manifesting symptoms of the disease or in individuals who are asymptomatic.
WorkplaceTesting explains Hepatitis B Surface Antigen
There are five hepatitis viruses known to affect the human body. Among these is hepatitis B. While some individuals' immune systems are able to resolve a hepatitis B infection, others may suffer chronic infections. Long-term infections may damage the liver resulting in scarring, cirrhosis or cancer.
Once exposed to hepatitis B, a person may test positive for the hepatitis B surface antigen (HBcAg) in as soon as one week. However, after 2 to 3 months, the HBcAg test may be negative despite the individual still carrying the hepatitis B virus. Thus, a patient may be asked to undergo further testing if a Hepatitis B infection is suspected despite a negative HBcAg result.