After contracting the HIV virus, the number of days it takes to test positive depends on the type of HIV test used and how soon your body starts producing detectable levels of the virus or antibodies. This period is called the window period.
For most people, HIV will show up on a nucleic acid test (NAT), which detects the virus itself, within 10 to 33 days after exposure. This is the most sensitive test but also the most expensive and not commonly used for routine screening.
The antigen/antibody test, which is widely used in many hospitals and clinics, can usually detect HIV infection within 18 to 45 days. It looks for both the p24 HIV antigen and antibodies your body creates in response to the virus.
Meanwhile, the rapid antibody tests or home tests, which only detect antibodies, typically take longer about 23 to 90 days after exposure to return a positive result.
It’s important to know that during this window period, a person can still spread the virus to others even if they test negative.
If you think you’ve been exposed to HIV, it’s critical to speak to a healthcare provider and consider post-exposure prophylaxis (PEP) within 72 hours to reduce your risk.