Can a Pap Smear Detect STDs Like Chlamydia or Gonorrhea?

One of the most pervasive myths about women’s health. You leave your smear test appointment congratulating yourself on having “had your STI check up”. When in reality, you did not get checked for STIs at all. Understanding the difference could be important for your health.

A Pap smear (cervical screening) and an STI test are not the same thing. Sure they can be done on the same day, in the same clinic room, by the same doctor and even use a similar-looking tool. But they do not test for the same things. If you think that your annual cervical screen has been giving you peace of mind as your sole method of Pap smear STD testing. Then this article is going to enlighten you (in a good way) on exactly what the test screens for. And what you need to request separately. 

What Does a Pap Smear Actually Test For?

The Pap smear test collects a small sample of cells from your cervix, which is then analysed in a lab for abnormal changes that may develop into cervical cancer if they’re not treated.

Primary HPV testing became the standard first line of testing used by the NHS Cervical Screening Programme in England from December 2019. This means your sample is first analysed for high-risk strains of human papillomavirus (HPV). If HPV is detected, the sample will then be analysed for cell abnormalities using cytology. If no HPV is detected, the sample is reported as negative and you will be recalled at your next routine appointment.

Essentially, while cervical screening does test for one STI HPV it only does so because HPV is a virus that can cause cervical cancer, it’s not looking for infections as part of a wider STI screen. The NHS Cervical Screening Programme exists to prevent cancer, not to provide sexual health screening.

Translated into plain English: a smear test does not tell you if you have chlamydia, gonorrhoea, syphilis, herpes, HIV, hepatitis B or hepatitis C, or trichomoniasis. If you want to check whether you have these infections, you have to ask for an STI test.

Why So Many People Confuse the Two

Confusion about these two tests is understandable. They often occur at the same appointment. They may involve the use of a speculum. They may involve the taking of a swab. Both pertain to your sexual and reproductive health. And the timing is similar: many people fit their smear into the same year as their “women’s health MOT.”

The sexually-transmitted aspect of HPV doesn’t help either. If you are getting tested for one STI, logic dictates that others must be tested for too. They are not. 

Cause for more confusion: occasionally a smear identifies inflammation or other change that causes a clinician to think about STIs. But that is known as a secondary finding. Even if you have chlamydia or gonorrhoea, a Pap smear will not reliably identify those infections. They can only be found through molecular testing.

Can a Pap Smear Detect Chlamydia or Gonorrhoea Under Any Circumstances?

Okay, now here’s where things can get slightly confusing. As clinicians can take a swab for chlamydia and gonorrhoea from the same speculum exam they use to collect a smear sample, if your clinician also collects an extra cervical/swab vaginal swab during your appointment and sends it for processing as a nucleic acid amplification test (NAAT), then yes, std tests from pap smear can detect chlamydia and gonorrhoea from that additional swab sample.

However, this NAAT test has to be specifically requested and ordered by your clinician. The sample collected for your cervical screening (smear) test does NOT get screened for bacterial STIs as part of the process. Nucleic acid amplification testing (NAAT) is a different type of test altogether that uses a different laboratory processing method to look for bacterial DNA or RNA. The UK Health Security Agency (UKHSA) recommends NAAT from vaginal or cervical swabs as the best way to test for both Chlamydia trachomatis and Neisseria gonorrhoeae infections in females.

The main thing to know is that chlamydia and gonorrhoea are ONLY detected during a Pap smear if your doctor adds on and separately processes an STI swab during your visit, it’s not a routine part of the Pap test.

What the smear cannot detect, even with an additional swab at the same visit:

• HIV  requires a blood test

• Syphilis  requires blood tests or a swab from any active sore

• Herpes (HSV-1 and HSV-2)  typically diagnosed via a swab from an active lesion, or serology

• Hepatitis B and C  diagnosed through blood tests only

• Trichomoniasis  usually requires a specific vaginal swab and microscopic examination or NAAT

Each of these infections has its own testing method. None of them can be detected from a standard cervical screening sample.

What Happens During a Cervical Screen vs. a Dedicated STI Screen

Understanding the distinction between these two tests helps clarify why they cannot simply be bundled into the same sample.

During cervical screening:

1. A speculum is used to gently open the vaginal walls

2. A small brush is used to collect cells from the outer and inner cervix

3. The sample is placed in a liquid preservation medium

4. The laboratory first tests for high-risk HPV

5. If HPV is found, cytology (cell analysis) is performed

6. Results are sent back within a few weeks

During a dedicated STI screen:

1. A vaginal or cervical swab is taken (sometimes self-collected)

2. In some cases, a first-catch urine sample is also taken

3. Blood samples may be drawn for HIV, syphilis, and hepatitis

4. Swabs are sent to a microbiology lab for NAAT processing

5. Results are typically returned within 24–72 hours

The British Association for Sexual Health and HIV (BASHH) recommends NAAT as the gold standard for detecting chlamydia and gonorrhoea in women, using vaginal or cervical swab samples. This is a distinct process from cervical cytology or HPV testing.

Who Should Be Getting STI Testing and How Often

NHS England's National Chlamydia Screening Programme advises that everyone under the age of 25 years who are sexually active should have a chlamydia screening test as part of their routine care. If you are aged 25 or over, NHS advice is that you should consider having a chlamydia test if you have: a new sexual partner, more than one sexual partner, had sex without a condom or if your partner has another STI.

Testing for gonorrhoea, syphilis and HIV is recommended for anyone who is thought to be at risk and all new patients attending the clinic are routinely offered a full sexual history and screen for all STIs.

If any of the following apply to you, it is worth asking specifically for STI testing alongside or separate from your cervical screen:

• You have a new sexual partner

• You have had unprotected sex

• You have noticed unusual vaginal discharge, pain, or bleeding between periods

• A previous partner has informed you of an STI diagnosis

• You have not been tested in the past 12 months

These symptoms do not confirm an STI. Many infections cause no symptoms at all  but they are good reasons to request targeted testing rather than relying on a smear appointment as your only check.

How STI Testing Works at a Gynaecology Clinic

The difference if you are booking into a gynaecology clinic in London as opposed to a sexual health service is broadly the same. At myGynaePlus the sexual health element of your gynaecology consultation includes discreet on-site STI screening and vaginal swabs which are then processed via The Doctors Laboratory (TDL), one of the UK’s largest independent pathology providers. That means you can book cervical screening, STI testing and a whole host of hormonal/reproductive health blood tests at the same appointment if clinically necessary.

What differs from a traditional GP smear appointment is that you have the benefit of a clinical consultation first. This allows your gynaecologist to decide which combination of tests are right for your unique history and symptoms. You’re not just sending off an anonymous smear kit – you’re having a conversation with your doctor about what you actually need testing for.

A Quick Reference: What Each Test Checks For

Cervical screening (smear test):

• High-risk HPV strains

• Abnormal cervical cell changes (cytology, if HPV positive)

What it does NOT detect:

• Chlamydia (without a separate NAAT swab)

• Gonorrhoea (without a separate NAAT swab)

• Syphilis

• HIV

• Herpes

• Hepatitis B or C

• Trichomoniasis

Dedicated STI tests:

• Chlamydia: NAAT from vaginal/cervical swab

• Gonorrhoea: NAAT from vaginal/cervical swab; culture for antibiotic sensitivity

• Syphilis: blood test

• HIV: blood test or oral swab

• Herpes: swab from lesion or blood test

• Hepatitis B/C: blood test

• Trichomoniasis: vaginal swab, wet mount microscopy or NAAT

  
  

The Bottom Line on Pap Smear STD Detection

Your smear test is only one aspect of your health. Thanks to the NHS cervical screening programme cervical cancer rates have been massively reduced in the UK, and with HPV primary testing our programme has never been more effective or personalised.

But it does not cover everything. For STI screening you need to order dedicated STI testing, and you are fully within your rights to ask for that during any gynaecology or sexual health appointment.

At myGynaePlus we offer cervical screening with Pap and HPV and cytology follow-up, as well as confidential STI screening and vaginal swabs through our gynaecology service. If you're unsure which tests are necessary for you, then booking a consultation with one of our gynaecologists is the best way to have that question answered.

Don't let a normal smear result trick you into thinking you'll have a clear STI screen. They are two separate tests. Book appropriately. 

Frequently Asked Questions

Does a normal smear result mean I do not have chlamydia?

No. A normal cervical screening result means no high-risk HPV was found and your cervical cells appear normal. It says nothing about chlamydia, gonorrhoea, or any other bacterial STI. Chlamydia often causes no symptoms at all and requires a separate NAAT swab or urine test to detect.

Can I ask for STI testing at the same appointment as my smear?

Yes. At most private gynaecology clinics and sexual health services, you can arrange both at the same appointment. A separate swab will be taken for STI testing and processed independently from your smear sample. At myGynaePlus, STI screening is available as part of the gynaecology consultation.

How is gonorrhoea tested in women if not through a smear?

Gonorrhoea in women is tested using a nucleic acid amplification test (NAAT), typically from a vaginal or cervical swab. BASHH guidelines recommend this as the first-line detection method. 

Is HPV the same as an STI? Why does the smear test for it?

HPV is a sexually transmitted virus, so yes  it is technically an STI. The smear tests for high-risk HPV strains because those strains are responsible for nearly all cases of cervical cancer. The test is not designed as an STI screen in the clinical sense, but rather as a targeted cancer prevention measure. Finding HPV does not mean you will develop cervical cancer, but it does mean you need closer monitoring.

What symptoms should prompt me to get STI testing rather than waiting for my next smear?

You should arrange STI testing if you notice unusual vaginal discharge (particularly if it has changed in colour, consistency, or smell), pain during sex, burning when passing urine, lower abdominal pain, or bleeding between periods or after sex. You should also get tested if a partner discloses a diagnosis, or if you have had unprotected sex with a new partner.