In medicine, the window period for a test designed to detect a specific disease (particularly infectious disease) is the time between first infection and when the test can reliably detect that infection.
The window period for HIV may be up to three months, depending on the test method and other factors.
RNA based HIV tests has the lowest window period.
[1][2] Two periods may be referred to as window period in hepatitis B infection: [citation needed] During the window of HBsAg to HBsAb seroconversion, IgM anti-core (HBc-IgM) is the only detectable antibody.
This window period does not occur in persons who develop chronic hepatitis B, i.e. who continue to have detectable HBV DNA for greater than 6 months (HbsAg remains positive), or in people who develop isolated HBcAb positivity, i.e. who lose HBsAg, but do not develop HBsAb (HBV DNA may or may not remain positive).