This page is general health information, not medical advice. It cannot tell you whether you have an infection. A clinician can, and the testing options on this site are a good place to start.

You had a possible exposure, and now you want to know when a test can give a useful answer. That is a fair question, and the answer depends on the infection and the type of test.

This guide walks you through it step by step. It covers the CDC window periods, when to test now and again later, what to do in the first 72 hours, and where to get tested in Atlanta.

What a window period is

A window period is the time between an exposure and the point when a test can reliably pick up an infection. Test too early and the result may come back negative even though the test is working as designed.

That is why a negative result soon after an exposure can be followed by a second test later. A clinician can tell you what a specific result means for you.

The window period for HIV is the best documented. The CDC publishes clear ranges for each type of HIV test. For many other infections, the CDC does not list one fixed number of days, and a clinician helps you pick the timing.

What you need before you start

The date of the exposure. If there were several, write down the most recent date and the first date.
A short list of what happened. Which body parts were involved (genital, anal, oral) and whether a condom or other barrier was used. This helps a clinician choose the right tests and the right swab or sample.
Any symptoms and their start dates. Our guide to STD symptoms, when to test and where explains what people commonly notice. Many infections cause no symptoms at all.
Your medicine list, including any PrEP you take.
A phone and a calendar to book the first test and a follow-up date.
Insurance information, if you have it. Several Atlanta options do not require it.

Step 1: Check whether you are inside the 72-hour window

Do this first. If the exposure was in the last 72 hours, time matters more than testing.

The CDC says post-exposure prophylaxis (PEP) for HIV should be started as soon as possible and within 72 hours of a possible exposure. PEP is a medicine that only a clinician can prescribe. The clinician decides if it is right for you.

The Georgia Department of Public Health HIV Prevention Program provides PEP and PrEP information and runs the Georgia AIDS & STI InfoLine at 1-800-551-2728. The Fulton County Board of Health and AID Atlanta also run HIV prevention services. Call the clinic first and say you are asking about PEP, since the clinic's public pages do not say whether each site offers it on the same day.

If you are outside the 72-hour window, you can still get tested and talk with a clinician about next steps. Skip to Step 2.

The CDC's 2024 doxy-PEP guidance is a separate option. It describes a clinician-prescribed medicine taken after sex to lower the chance of certain bacterial STIs for some groups, including gay and bisexual men and transgender women who have had a bacterial STI in the past year. It also has a 72-hour timeframe. A clinician decides whether it fits your situation. The Fulton County Board of Health lists DoxyPep among the services at its 10 Park Place Health Center.

Step 2: Look up the window period for the infection you are worried about

HIV windows come from the CDC's HIV testing page. The CDC lists the range as the number of days after an exposure.

Infection and test type	CDC window period or guidance
HIV: nucleic acid test (NAT), blood	About 10 to 33 days after exposure, per the CDC
HIV: antigen/antibody test, lab blood draw	About 18 to 45 days after exposure, per the CDC
HIV: antigen/antibody test, fingerstick	About 18 to 90 days after exposure, per the CDC
HIV: antibody rapid test or self-test	About 23 to 90 days after exposure, per the CDC
Chlamydia, gonorrhea, trichomoniasis	The CDC STI Treatment Guidelines (2021) do not give one fixed window. A clinician picks the timing and the sample type.
Syphilis	The CDC STI Treatment Guidelines (2021) do not give one fixed window. For people evaluated after sexual assault, the CDC suggests follow-up testing for HIV and syphilis at about 6 weeks, 3 months and 6 months.
Herpes, HPV, hepatitis B and C	Timing depends on the infection, symptoms and test. Ask a clinician. The CDC does not list a single window for these.

If a test type is not on this table, a clinician or the health department can tell you the timing for it.

Step 3: Test now, and plan a second test later

Testing early and testing again are both useful, and they answer different questions.

Test soon after the exposure. A first test gives a baseline, and a clinician can address symptoms or treat infections that already show up. Some infections can be detected earlier than others.
Retest after the window period for your test type. For HIV, that means using the CDC ranges above. A test taken at the end of its window gives a more reliable answer than one taken at the start.
Book the second visit before you leave the first. It is easy to forget a follow-up once the first result is back.

The CDC also recommends that people treated for chlamydia or gonorrhea be retested about three months after treatment, because reinfection is common. Your clinician will tell you what applies to you.

Step 4: Choose the right test and the right sample

Tell the clinician where the exposure happened. The CDC STI Treatment Guidelines (2021) describe testing at the throat, rectum or genitals depending on the type of sex. A urine test alone does not check every site.

Ask which tests are included in your visit. AID Atlanta's testing page says it offers a fourth-generation HIV blood test or an INSTI rapid test, and free screening for chlamydia, gonorrhea and syphilis.

Our guide to STD testing in Atlanta, where to get tested and what it costs goes deeper on the visit itself.

Step 5: Pick a place to get tested in Atlanta

Atlanta has free and low-cost options. You can see the full local list in our Atlanta clinic list. Here are the ones most relevant to a post-exposure visit.

AID Atlanta Wellness Center

AID Atlanta lists free HIV and STI testing, with free treatment for reactive screening results. It is at 1438 W Peachtree Street NW. Its website lists testing Monday to Friday, 9:30 a.m. to 5:30 p.m., with walk-ins welcomed. The STI testing line is (404) 870-7741.

Fulton County Board of Health, 10 Park Place Health Center

This center is at 10 Park Place S.E., 5th floor. The Board of Health lists STI screening and treatment, HIV testing, PrEP and DoxyPep. Fees on its sexual health page follow a sliding scale for people without insurance. Hours listed are Monday to Friday, 8:00 a.m. to 12:00 p.m. and 1:00 p.m. to 4:30 p.m., and the last walk-in appointment is at 3:00 p.m. Call (770) 520-7500.

Other Fulton County health centers

The Board of Health also lists STI services at Adamsville Regional Health Center, 3700 MLK Jr. Drive S.W., (770) 520-7323, and Neighborhood Union Health Center, 186 Sunset Avenue N.W., (770) 520-7351. Its pages note that appointments are recommended, and they show different hours for Neighborhood Union, so call first to confirm. The Board of Health says its sexual health clinics serve Fulton County residents ages 14 and up.

Teen Health Clinic

For ages 12 to 21, the Teen Health Clinic at Adamsville offers STI exams and HIV counseling and testing. The Board of Health says fees are based on income and family size, and that no teen is turned away for inability to pay. The number is 770-520-7323.

Planned Parenthood East Atlanta Health Center

This center is at 440 Moreland Avenue SE, 404-688-9300. Its page lists STD testing and treatment, HIV testing and PrEP. Insurance is not required, and the page lists cash and card payment. It does not state a sliding scale, so ask about cost when you call.

If you live in the DeKalb part of Atlanta, DeKalb Public Health serves that area. Check its website or call for current services.

You can also use the CDC's locator at gettested.cdc.gov to find testing sites by ZIP code.

The CDC also links to free HIV self-tests ordered online through the Together TakeMeHome program. Georgia DPH lists an at-home HIV self-test by online request, but its page does not state cost or eligibility. Remember that self-tests have their own window period, shown in the table above.

Step 6: Get your results and plan the next step

Ask how and when you will hear back. Some tests give a result in minutes, and others take days.
Ask what a negative result means at this point. A clinician can tell you whether it is final or whether a repeat test is advised, based on your exposure date.
If a result is positive, ask about treatment. Bacterial STIs and trichomoniasis are curable with treatment from a clinician. HIV and herpes are not curable but are treatable and manageable. HPV is also not curable, though many infections clear on their own according to the CDC.
Ask about partner notification. Georgia allows expedited partner therapy, according to the CDC's legal status page for Georgia, and Georgia DPH says local health departments can tell you how to find EPT services. Ask your clinician whether it applies to you.

Georgia DPH says all health care providers and labs must report certain conditions. Per its notifiable disease table, syphilis is reported immediately, and chlamydia, gonorrhea and HIV are reported within seven days. This is routine public health reporting, and clinics handle it for you.

Tips and common mistakes to avoid

Testing once and stopping. A single early negative may not be the last word. Plan a second test using the window for your test type.
Using the wrong clock. The window period starts at the last possible exposure, not at the first date.
Waiting for symptoms. The CDC notes that many STIs cause no symptoms, so symptoms are not a reliable signal.
Missing the 72-hour PEP timeframe. If it applies, call a clinic or the InfoLine first and schedule testing second.
Leaving out details. Be specific with the clinician about sites of exposure. It helps them pick the correct samples.
Assuming a negative means you can skip protection. Ask about condoms, PrEP and vaccines, and talk through options with a clinician.
Skipping the question about cost. Ask before the visit. Many Atlanta options are free or sliding scale.

What results can look like

A negative result after the full window period for your test generally suggests the infection was not detected. A negative result before the window period ends may be followed by a repeat test. A positive result usually leads to a confirmation test and a conversation about treatment.

No test is perfect, and only a clinician can interpret a result for your situation.

In Georgia, testing is common because infections are common. For example, the Georgia DPH OASIS data tool reported 978.7 chlamydia cases per 100,000 people in Fulton County in 2023, and 646.4 per 100,000 statewide in the CDC's 2023 state ranking table. Getting tested is routine health care, and clinicians see these questions every day.

Quick checklist

Write down your exposure date.
If it was within 72 hours, call a clinic or the Georgia AIDS & STI InfoLine about PEP right away.
Look up the window for the test you plan to take.
Book a first test, and a second test for after the window.
Ask your clinician what each result means for you.

When to Get Tested After Exposure: STD Window Periods Explained