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STD Testing in O'fallon, Missouri

5 STD and HIV testing locations in O'fallon.

Verify with the clinic before visiting. Hours, services, fees and appointment rules change. Call ahead to confirm. This directory is for information only and is not medical advice. In an emergency, call 911.

Mercy – Mercy Clinic Primary Care

300 Winding Woods Dr, Ste 214, O'fallon, MO 63366 · (636) 614-3280
Sliding scaleChlamydiaGonorrheaSyphilisHerpesHIVRapid HIVHepatitis CHepatitis B
Mon 8:00am – 4:30pm; Tue 8:00am – 4:30pm; Wed 8:00am – 4:30pm; Thu 8:00am – 4:30pm; Fri 8:00am – 4:30pm

Mercy – Mercy Clinic Primary Care Winghaven

2223 Technology Dr, Ste 40, O'fallon, MO 63368 · (636) 755-4400
Sliding scaleChlamydiaGonorrheaSyphilisHerpesHIVRapid HIVHepatitis CHepatitis B
Mon 8:00am – 5:00pm; Tue 8:00am – 5:00pm; Wed 8:00am – 5:00pm; Thu 8:00am – 5:00pm; Fri 8:00am – 5:00pm

Mercy-GoHealth Urgent Care – O'Fallon

2991 State Hwy K, O'Fallon, MO 63368 · (636) 435-2333
ChlamydiaGonorrheaHerpesHepatitis CHepatitis B
Mon 8:00am – 8:00pm; Tue 8:00am – 8:00pm; Wed 8:00am – 8:00pm; Thu 8:00am – 8:00pm; Fri 8:00am – 8:00pm; Sat 9:00am – 5:00pm; Sun 9:00am – 5:00pm

Total Access Urgent Care – O'Fallon North Urgent Care

502 S Main St, O'Fallon, MO 63366 · (636) 409-1132
ChlamydiaGonorrheaSyphilisHerpesHIVRapid HIVHepatitis B
Mon 8:00am – 8:00pm; Tue 8:00am – 8:00pm; Wed 8:00am – 8:00pm; Thu 8:00am – 8:00pm; Fri 8:00am – 8:00pm; Sat 8:00am – 8:00pm; Sun 8:00am – 8:00pm

Total Access Urgent Care – O'Fallon South Urgent Care

4201 Hwy K, O'Fallon, MO 63368 · (636) 294-8540
ChlamydiaGonorrheaSyphilisHerpesHIVRapid HIVHepatitis B
Mon 8:00am – 8:00pm; Tue 8:00am – 8:00pm; Wed 8:00am – 8:00pm; Thu 8:00am – 8:00pm; Fri 8:00am – 8:00pm; Sat 8:00am – 8:00pm; Sun 8:00am – 8:00pm

Frequently asked questions

Where can I get STD testing in O'fallon, MO?

This page lists 5 STD/HIV testing locations in O'fallon, MO from the CDC NPIN directory. Call ahead to confirm services and hours.

Is there free STD testing in O'fallon, MO?

None of the listed locations currently say they offer free STI or HIV testing. Some list sliding-scale fees or accept Medicaid. Call to ask about low-cost options.

Do I need an appointment?

3 locations here say no appointment is required. Others may need an appointment. Call before you go.

Can I get a rapid HIV test?

4 locations here list rapid HIV testing, which usually gives results during the same visit.

Which tests should I ask for?

Common tests include chlamydia, gonorrhea, syphilis, HIV and sometimes herpes or hepatitis. Which ones you need depends on your situation, so a clinician can help you decide. CDC recommends everyone ages 13 to 64 get tested for HIV at least once.

Is STD testing confidential?

Health care providers must keep your health information private. Some public health clinics offer anonymous HIV testing. Ask the clinic about their privacy policy.

Data: CDC NPIN. Page built 2026-11-03.