What Happens If You Get an STD?
Worried about a sexually transmitted infection after unprotected sex, oral sex or a new partner? Understand the symptoms, complications, treatment options and how to arrange confidential private STI testing in London.
Depending on the infection, untreated STIs can cause inflammation, pelvic or testicular complications, affect fertility or lead to wider health problems. Many bacterial STIs can be cured with appropriate antibiotics, while infections such as HIV and genital herpes can be managed with treatment.
The most useful next step is appropriate STI testing at the correct time, followed by treatment or clinical advice when needed.
You cannot reliably confirm or exclude an STI from symptoms alone.What happens to your body when you catch an STI?
The effects depend on the organism, the part of the body affected and whether the infection is diagnosed and treated.
Some infections cause burning during urination, unusual discharge, sores, itching or pelvic discomfort. Others may remain unnoticed.
Chlamydia and gonorrhoea, for example, can sometimes cause complications when untreated, even when early symptoms are mild or absent.
STIs can also affect the throat or rectum after exposure at those sites. This is why the correct sample matters just as much as choosing the right test.
What should you do if you think you have an STI?
Exposure → Testing → Results → Care
A useful STI investigation depends on the exposure, anatomical site and testing window.
When did it happen? Was contact genital, oral or anal?
Blood, urine, vaginal, throat or rectal swabs as appropriate.
Consider positive, negative or inconclusive findings alongside timing.
Treatment, repeat testing, partner notification or referral when needed.
Eight important questions about STDs and STIs
Clear answers to common questions about infection, symptoms, transmission and treatment.
Is STD very serious?
Some STIs are straightforward to treat, while others can cause serious complications if untreated.
Potential consequences include pelvic inflammatory disease, infertility, testicular inflammation and chronic infection.
A positive result does not automatically mean permanent damage. Early diagnosis and appropriate care matter.
Explore STI screening at MDC →How common is STD from BJ (oral sex)?
Oral sex can transmit infections including gonorrhoea, syphilis, herpes and, in some circumstances, chlamydia.
HPV can also spread through sexual contact. HIV transmission through oral sex is generally much less likely than through vaginal or anal sex.
There is no single reliable percentage that applies to every oral-sex encounter.
A throat swab may be required. A genital urine test alone cannot exclude a throat infection.
Ask MDC about appropriate STI samples →How quickly do STDs go away?
The answer depends on the infection and treatment. Some bacterial STIs can be cured with appropriate antibiotics.
Viral infections such as HIV and genital herpes require a different approach and may need ongoing treatment.
Symptoms disappearing does not necessarily mean the infection has cleared.
Is STD 100% curable?
No. Many bacterial STIs, including chlamydia, gonorrhoea and syphilis, can be cured with appropriate treatment.
HIV and genital herpes are not currently routinely curable, although effective treatments are available.
A previous cure does not prevent reinfection.
When are the first signs of an STD?
Symptoms may develop within days, weeks or longer depending on the infection. Some people never develop noticeable symptoms.
Possible signs include unusual discharge, burning when urinating, genital sores, itching, pelvic pain, rash or bleeding.
Symptoms and test-detection windows are not the same thing.
Explore testing at MDC →What STD is not curable?
HIV and genital herpes are examples of infections that are not routinely curable with current standard treatment.
Effective HIV treatment can suppress the virus to undetectable levels. Sustained viral suppression prevents sexual transmission (U=U).
Antiviral medicines can help control genital herpes outbreaks.
What does STD do to a woman?
STIs may cause unusual discharge, pain when urinating, pelvic pain, bleeding or pain during sex.
However, many women have no symptoms. Untreated chlamydia or gonorrhoea can sometimes lead to pelvic inflammatory disease and fertility complications.
Vaginal swabs, blood tests or other investigations may be appropriate.
Explore women’s STI testing at MDC →How to 100% know if you have an STD?
You cannot determine STI status from symptoms or appearance alone.
Appropriate laboratory tests provide the best evidence, but accuracy depends on the infection, sample type and timing.
A negative test during the window period may need repeating. No single routine test checks every STI at every site.
Choose an MDC sexual health profile →Can STI tests be inconclusive?
Yes. An STI test can sometimes return an inconclusive, indeterminate or invalid result. This does not automatically mean you have an infection.
An inconclusive result means the laboratory could not provide a sufficiently clear positive or negative interpretation from that test.
Sample limitations
The sample may be insufficient, unsuitable or affected by substances that interfere with the testing process.
Borderline findings
Some assays may produce borderline or indeterminate results requiring further interpretation or confirmatory testing.
Timing of testing
Testing too soon after exposure can produce a negative result before the infection is detectable. This is not necessarily reported as inconclusive.
STI test results example: what does a report look like?
STI laboratory reports usually identify the infection tested, the sample collected and the reported result.
Below is a simplified educational example. It is not an actual MDC patient report, and individual laboratory formats vary.
| Test | Example result | What it may mean |
|---|---|---|
| Chlamydia NAAT/PCR | Not detected | Chlamydia genetic material was not detected in the submitted sample. |
| Gonorrhoea NAAT/PCR | Detected | A positive finding requiring appropriate clinical management and, where indicated, additional testing. |
| HIV laboratory screening | Non-reactive | No reactive screening signal was found. Timing since exposure still matters. |
| Syphilis screening | Indeterminate | Further testing or interpretation may be required before determining status. |
A negative result only applies to the infection and sample tested, and must be interpreted in relation to the testing window.
If you are unsure which tests to arrange, view MDC’s Sexual Health profiles or contact the clinic before booking.
What is private STI testing?
Private STI testing allows patients to arrange sexual health screening through an independent healthcare provider rather than waiting for an NHS appointment.
Depending on the provider, patients may be able to book blood tests, urine tests and swab-based investigations for specific infections or broader screening profiles.
Marylebone Diagnostic Centre offers private sexual health testing from its Baker Street clinic in Central London. Patients can review available profiles, compare test inclusions and arrange an appointment.
Where can I get confidential STI testing in London?
You can arrange confidential STI testing through NHS sexual health clinics or private providers such as Marylebone Diagnostic Centre.
MDC is located at 73 Baker Street, London W1U 6RD and provides private sexual health testing for patients seeking a Central London appointment.
Sexual health information is sensitive medical information. Confidentiality means it should be handled according to applicable healthcare privacy and data-protection requirements. It does not mean that results can never be shared where disclosure is legally required or clinically authorised.
If discretion is particularly important, ask the clinic how appointments, communications and results are handled before booking.
Private STI testing in Baker Street, London
Choose from MDC’s sexual health profiles and arrange testing based on your needs. No GP referral is required for routine private sexual health testing.
73 Baker Street, London W1U 6RD
What are the best private STI testing services available in the UK?
The best private STI testing service is one that offers the correct investigations for your exposure, reliable laboratory methods, clear results and appropriate follow-up.
There is no single provider that is automatically best for every patient. The right choice depends on location, the infections being investigated, test timing, sample availability and clinical needs.
Appropriate tests
Check whether the provider offers the required blood, urine or site-specific swab tests.
Clear pricing
Understand which infections are included and whether further testing has additional charges.
Useful next steps
Know how positive, inconclusive or early negative results will be interpreted and followed up.
Patients can compare the available investigations before booking rather than relying on a generic “full STI test” description.
Compare MDC Sexual Health Profiles →Which private STI test should you book at MDC?
MDC offers different sexual health profiles. Choose according to your exposure, symptoms and the infections that need investigation.
Sexual Health Basic
Includes HIV 1&2/p24 antigen, syphilis, chlamydia and gonorrhoea testing, subject to suitable timing and sample requirements.
View Basic ProfileSexual Health Plus
A broader genital PCR panel. Not every included organism requires routine screening or treatment. Does not replace HIV and syphilis blood testing.
View Plus ProfileAdvanced Sexual Health Profile
A broader MDC screening option including core STI investigations and additional tests. Confirm the full panel, sample requirements and exposure-site coverage.
View Advanced ProfileTell MDC when the exposure happened, whether it involved oral, vaginal or anal sex, and whether you have symptoms. This helps determine which available tests and samples may be relevant.
Why one STI test may not check every infection
Genital exposure
Urine or genital swab testing may be appropriate for selected infections such as chlamydia and gonorrhoea.
Oral or anal exposure
Throat or rectal swabs may be required. Genital urine testing does not exclude infections at these other sites.
Blood-borne infections
HIV, syphilis and hepatitis investigations generally require blood tests and appropriate timing.
Concerned about an STI? Contact MDC
You do not need to know which test to book before speaking to our team.
Simply say: “I’ve had a possible STI exposure and would like to know which tests I need and when.”
MDC can explain the available sexual health profiles, sample requirements and appointment options.
Seek prompt medical assessment for severe pelvic pain, fever with significant genital symptoms, suspected infection during pregnancy or concerning testicular symptoms. Sudden severe testicular pain requires emergency assessment.
For possible HIV exposure within 72 hours, seek urgent advice about PEP without waiting for a routine screening appointment.
NHS: Sexually transmitted infections
This article provides general information and does not replace individual medical assessment. Test availability, suitability, pricing and timing should be confirmed with the clinic. Medical reviewer approval is pending.
Worried about an STI? Get the right test, at the right time.
Whether you have symptoms, have had a recent sexual exposure or simply want confidential screening, MDC offers private STI testing in Central London.
Explore our available sexual health profiles, understand which infections are included and arrange an appointment at our Baker Street clinic.
Marylebone Diagnostic Centre · 73 Baker Street, London W1U 6RD
