Upon finding out that you may have been exposed to HIV, you may want to get tested right away; however, HIV tests do not detect HIV immediately after HIV exposure. According to the CDC’s HIV testing guidance, the time between a possible exposure and the point when a test can detect HIV is called the “window period.”
Here are the various methods of testing and their unique window periods according to the CDC:
- A nucleic acid test, often called a NAT, looks for the virus itself in venous blood. CDC says this test usually detects HIV 10 to 33 days after exposure.
- A lab-based antigen/antibody test using blood from a vein usually detects HIV 18 to 45 days after exposure.
- A rapid antigen/antibody test using a finger stick usually detects HIV 18 to 90 days after exposure. Antibody-only tests usually detect HIV 23 to 90 days after exposure. Timing matters because the result depends on the test type and the date of possible exposure. If someone tests too early, the result may not give the final answer. HIV.gov explains that a person who tests negative during the window period needs another test after the window period for that specific test to ensure they are negative.
Your provider will take into account the time that has elapsed since the potential exposure to HIV and pick the test that’s right for you. According to the National Institute of Health HIV information page, HIV is not typically diagnosed based on one test; the clinic will most likely conduct a follow-up test to ensure that the results are accurate.
Getting Tested After HIV Exposure
If the possible exposure occurred within the last 72 hours, ask about Post-Exposure Prophylaxis (PEP). CDC’s PEP guidance describes PEP as an emergency medication option that must be started within 72 hours (3 days) after a possible exposure. The CDC also states that to get the most out of PEP, begin taking it as soon as possible, as “Every hour counts.”
If you have concerns about contracting HIV, ask your provider about Pre-Exposure Prophylaxis (PrEP), a preventative medication that can be taken orally or through an injectable route to significantly reduce the risk of contracting HIV.
At Orenda Health & Wellness, HIV testing and prevention centers on raising awareness and providing education about the next steps. After HIV exposure, Orenda offers confidential HIV and STD testing, HIV risk assessment, PrEP initiation and monitoring, PEP evaluation and prescribing, HIV counseling, routine HIV screening coordination, and linkage to care for new diagnoses through its HIV Testing and STI Services.
If you are unsure when to test, which test you need, or if PEP or PrEP belongs in the conversation, an appointment helps remove guesswork. A provider can review your timing, your risk, and the next step that fits your situation.
Quick Questions on HIV Exposure
Can I test the next day after exposure?
You can talk with a provider right away, but the CDC states that no HIV test can detect HIV immediately after exposure.
Which HIV test detects HIV earliest?
A NAT usually detects HIV earlier than other test types, often 10 to 33 days after exposure, according to the CDC’s HIV testing guidance.
Do I need another test after a negative result?
If you tested during the window period, HIV.gov says retesting after the window period may be needed.