STD Testing After Unprotected Sex in London – What You Need to Know

Reviewed by Dr Lauren Holland • Marylebone Diagnostic Centre
Results within 24 – 42 hours. Westminster residents receive 20% off.

Unprotected sex can lead to anxiety, uncertainty, and concern about sexually transmitted infections (STIs). Many Londoners search for clear guidance on how soon they can test, which infections are detectable, and where to get fast and confidential help. Clinically, we see a rise in patients attending for testing after a one-off encounter, a broken condom, or unexpected contact.

This guide explains the timing of accurate STD tests, the symptoms to watch for, and how Marylebone Diagnostic Centre in central London offers fast, private and discreet sexual health testing. Whether you have symptoms or simply want peace of mind, early testing helps you understand your health and take appropriate steps.

Why Testing After Unprotected Sex Is Important

Silent infections are common

Many STDs show no symptoms for days, weeks, or even months. Untreated infections can lead to long-term issues such as pelvic pain, fertility problems, and onward transmission.

Symptoms are not always reliable

Some patients report discomfort, burning or unusual discharge. Others feel completely normal but later test positive. A clinical test offers clarity.

Peace of mind

Testing removes uncertainty. Private blood and urine tests provide reliable answers within 24–42 hours.

How Soon Can You Get Tested After Unprotected Sex?

The timing depends on the infection. Testing too early may give false reassurance, while waiting too long may delay treatment. These are the typical detection windows:

Chlamydia and Gonorrhoea

• Can usually be detected from 7 days after exposure
• Earlier testing is possible if symptoms appear

HIV

• 28-day laboratory blood test detects most infections
• Some patients test at 14 days for early reassurance

Syphilis

• Most reliable from 28 days
• Early symptoms can appear sooner, so early testing is still useful

Trichomonas

• Detectable from 7–10 days

Herpes

• Requires symptoms for reliable swab testing
• Blood testing has limited value without symptoms

At MDC, clinicians can help you decide the right timing based on your situation.

Symptoms That May Appear After Unprotected Sex

Some infections produce symptoms within days, while others remain silent. Common signs include:

• Burning when passing urine
• Unusual discharge
• Lower abdominal pain
• Itching or irritation
• Painful intercourse
• Genital sores or ulcers
• Fever or swollen glands

Remember: most STDs show no symptoms at all, which is why testing is essential.

What Tests Are Available at Marylebone Diagnostic Centre?

We offer several fast and discreet sexual health profiles:

Full STI Panel (urine + blood)

Covers:

• Chlamydia
• Gonorrhoea
• HIV
• Syphilis
• Trichomonas
• Mycoplasma genitalium
• Ureaplasma species

Results usually return within 24–42 hours.

Advanced Sexual Health Panel (blood)

Ideal when you want a broader screen focusing on blood-borne infections.

Urine Culture & Analysis

For symptoms such as burning, discomfort or suspected urinary infection.

Genital Swabs (men and women)

Useful for symptomatic patients and for infections not detected in urine.

All tests are discreet, confidential, and carried out in private rooms.

Why Choose Private STD Testing in Marylebone?

Is NHS STI Testing Free in London?

Yes. NHS sexual health clinics offer free STI testing across the city.
However, many patients choose private testing because they want:

• Faster results
• More privacy
• Evening or next-day appointments
• No waiting rooms
• Doctor-reviewed results
• More comprehensive panels

MDC provides a clinical, discreet and supportive environment for anyone wanting a fast, accurate assessment.

Where Can I Get Tested in London After Unprotected Sex?

You can get tested at:

• Marylebone Diagnostic Centre (private, same-day, fast results)
• NHS sexual health clinics (free but may involve waits)
• Some pharmacies (limited test options)

MDC is a preferred choice for patients wanting speed, accuracy and confidentiality.

What Happens During an STD Test at MDC?

1. A private consultation to understand your situation
2. A urine sample, swab, or blood test depending on symptoms
3. Laboratory analysis
4. Results returned by secure email within 24–42 hours
5. A written explanation from Dr Lauren Holland

The process is simple, fast, and discreet.

Clinical Notes from MDC

Clinically, we see many patients who wait too long to test because they feel embarrassed or unsure of the timing. Early testing provides clarity and reassurance. If results are negative but exposure was recent, a follow-up test may be advised. Our team helps guide each patient based on their exposure, timing, and symptoms.

FAQs

Booking Your STD Test at Marylebone Diagnostic Centre

Marylebone Diagnostic Centre
73 Baker Street, London W1U 6RD
Tel: +44 7495 970109
Open Monday–Saturday, 08:00–16:00

Fast, private, and confidential STD testing with results in 24–42 hours.
Westminster residents receive 20% off all tests.

Quick Links

• Full STI Panel
• Advanced Sexual Health Panel
• Urine Culture & Analysis
• HIV Testing
• Chlamydia & Gonorrhoea Testing
• Syphilis Testing
• Book Your Sexual Health Test

Read More

• NHS – STIs: symptoms, testing, treatment
• British Association for Sexual Health and HIV (BASHH)
• CDC – Sexually Transmitted Infections (STIs)
• NHS – HIV testing