How long does it take for a blood test, such as HBsAg, to be positive after exposure to hepatitis B virus?
HBsAg will be detected in an infected person’s blood on the average of four weeks (range is one to nine weeks) after exposure to the virus. About one out of two patients will no longer be infectious by seven weeks after onset of symptoms and all patients, who do not remain chronically infected, will be HBsAg-negative by 15 weeks after onset of symptoms.
HBsAg will be detected in an infected person’s blood on the average of 4 weeks (range 1-9 weeks) after exposure to the virus. About 1 out of 2 patients will no longer be infectious by 7 weeks after onset of symptoms and all patients, who do not remain chronically infected, will be HBsAg-negative by 15 weeks after onset of symptoms.
