How Soon After Unprotected Sex Should You Get Tested for STIs?

The Anxiety of Waiting

If you've had unprotected sex and you're worried about STIs, your first instinct is probably to get tested immediately. We understand that urge – the uncertainty is stressful.

But here's the thing: testing too early can give you false reassurance. Each STI has a "window period" – the time between exposure and when a test can detect infection. Testing during this window may give a negative result even if you're infected.

Let's break down exactly when to test for each STI.

The Window Period Explained

After exposure to an STI, there's a delay before:

• The infection produces enough detectable markers (antibodies, antigens, or genetic material)
• Standard tests can identify the infection

Testing during the window period may miss a new infection. That's why timing matters.

STI-by-STI Testing Timeline

Chlamydia and Gonorrhoea

Window period: 2 weeks

When to test: From 14 days after exposure

Why this timing:

• NAAT tests (standard urine/swab tests) detect bacterial genetic material
• Takes about 2 weeks for infection to reach detectable levels
• Testing earlier may miss recent infections

Recommendation: Test at 2 weeks; no need to repeat if negative (unless symptoms develop)

HIV

Window period: Depends on test type

4th generation (antigen/antibody) test:

• Window: 4-6 weeks
• Detects 95%+ of infections by 4 weeks
• Most clinics use this test

Antibody-only tests:

• Window: 6-12 weeks
• Full accuracy at 12 weeks

When to test:

• Initial test at 4 weeks (most infections detected)
• Repeat at 12 weeks for definitive result

Syphilis

Window period: 4-6 weeks (up to 12 weeks for complete accuracy)

When to test:

• Initial test at 4-6 weeks
• Repeat at 12 weeks if initial test negative but concern remains

Why this timing:

• Blood tests detect antibodies, which take time to develop
• Very early syphilis may be missed
• Primary sore (chancre) may be visible before blood tests turn positive

Herpes (HSV)

Window period: 12 weeks for blood tests

When to test:

• If you have symptoms (sores/blisters): Get swabbed immediately
• If no symptoms: Blood test from 12 weeks post-exposure

Important notes:

• Blood tests detect antibodies, which take up to 12 weeks to develop reliably
• Swab tests on active sores are accurate immediately
• Blood testing isn't routinely recommended without symptoms (discuss with clinician)

Hepatitis B

Window period: 6 weeks to 3 months

When to test:

• Initial test at 6 weeks
• Repeat at 3 months if initially negative

Why this timing:

• Tests detect hepatitis B surface antigen (HBsAg)
• May be detectable from 4 weeks but can take longer
• 3-month test provides certainty

Hepatitis C

Window period: 6-12 weeks

When to test:

• Initial test at 6 weeks
• Repeat at 12 weeks for definitive result

Note: Hepatitis C is primarily transmitted through blood-to-blood contact; sexual transmission is less common but possible, especially with blood exposure.

Trichomoniasis

Window period: 2 weeks

When to test: From 14 days after exposure

Mycoplasma genitalium

Window period: 2-3 weeks

When to test: From 2-3 weeks after exposure

Note: Not always included in standard STI screens; may need to request specifically.

Quick Reference Table

What to Do While Waiting

Use Protection

• Use condoms for any sexual contact while awaiting results
• This protects partners in case you are infected

Don't Panic

• Anxiety is normal, but remember that most STIs are treatable
• Focus on taking responsible action rather than worrying

Watch for Symptoms

If you develop any symptoms before your test date, seek testing immediately:

• Unusual discharge
• Pain when urinating
• Sores or blisters
• Rash
• Flu-like symptoms with recent sexual exposure

Consider Early Testing Anyway

Early testing can:

• Detect existing infections from previous exposures
• Provide some reassurance (though repeat testing may be needed)
• Catch infections that became detectable sooner than average

Special Situations

Symptoms Before Window Period Ends

If symptoms develop, don't wait for the window period:

• Symptomatic infections can often be diagnosed immediately
• Seek testing and treatment promptly

Partner Notification

If you've been told a partner has an STI:

• Get tested regardless of window period
• You may be offered presumptive treatment for certain STIs
• Discuss with a healthcare provider

The Testing Process

What Comprehensive Testing Includes

A full STI screen typically involves:

• Urine sample: Chlamydia and gonorrhoea
• Blood sample: HIV, syphilis, hepatitis B
• Swabs (if indicated): Throat and rectal for gonorrhoea; genital for various infections

Where to Get Tested

• Sexual health clinics (free, confidential, no GP referral needed)
• Your GP
• Online testing services (home kits posted discreetly)
• Private clinics

Getting Results

• Some results available same day or within 48 hours
• Others may take up to 2 weeks
• You'll be contacted if results are positive
• No news often means negative, but always confirm

The Bottom Line

Testing too early can miss infections; testing at the right time gives reliable results. Use the timelines above to plan your testing, and don't let the waiting period lead to inaction.

If you're anxious, consider early testing with planned follow-up. And remember: whatever the result, STIs are common and treatable. Testing is the responsible choice.

Book Your Test

Ready to get tested? We offer confidential STI testing with expert guidance on timing. Book your appointment for peace of mind.