The window between infection and detection can be three months.
“There’s a period of time after a person is infected during which they won’t test positive. This is called the HIV “window period.”
The window period can be from 10 days to 3 months, depending on the person’s body and on the HIV test that’s used. During that time, you can test HIV-negative even though you’re HIV-positive. You can still get HIV from someone who is in the window period. In fact, there is evidence that a person in the window period is more likely to pass the virus on.”