Patient guide · Screening · 7 min read
Anal cytology screening, HPV-based screening for anal high-grade dysplasia and anal cancer prevention.
A liquid-based cytology sample from the anal canal to screen for anal high-grade squamous intraepithelial lesions (HSIL) and anal cancer. Offered to high-risk groups (people living with HIV, MSM, post-transplant, cervical HSIL history). Modern pathway includes co-testing with HPV.
Why patients choose us
- 01
The right hands
We route you to a clinician experienced in anal cytology and HPV co-testing — with onward high-resolution anoscopy (HRA) if the sample is abnormal.
- 02
Modern co-testing
Liquid-based cytology plus HPV genotyping — the pathway shown to improve sensitivity over cytology alone.
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Independent, and free
We are paid by no clinic, so the recommendation is impartial and costs you nothing.
Key facts
The six things worth knowing about anal cytology.
Screening is targeted, not universal. These six facts frame who benefits, what the test looks for, and what happens next.
In short
Liquid-based cytology plus HPV co-testing — abnormal results trigger high-resolution anoscopy.
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Definition
A liquid-based cytology sample from the anal canal.
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What it screens for
Anal high-grade squamous intraepithelial lesions (HSIL) and anal cancer.
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Who it is for
High-risk groups: HIV, MSM, post-transplant, cervical HSIL history.
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Co-testing with HPV
Adding HPV genotyping increases sensitivity over cytology alone.
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What abnormal triggers
Abnormal cytology triggers high-resolution anoscopy (HRA).
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Evidence base
The landmark ANCHOR trial showed that treating HSIL prevents anal cancer.
The problem
Anal cancer is preventable — screening is the route.
Anal HSIL is the treatable precursor to anal cancer. The ANCHOR trial confirmed that treating HSIL prevents progression. Cytology plus HPV co-testing catches it early — high-resolution anoscopy confirms it.
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Living with HIV?
You are in the highest-incidence group for anal HSIL. Annual screening is standard of care.
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MSM without HIV?
Elevated risk warrants targeted screening — we arrange cytology and HPV co-testing.
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Post-transplant or cervical HSIL?
Immunosuppression and multi-site HPV disease both raise anal HSIL risk — screening is offered.
Preparation and sampling
From preparation to result — what happens, in order.
Preparation is minimal. The sample takes under a minute. The result — cytology and HPV together — arrives within 7–10 days.
Phase 1 · Before
Preparation, 24 hours ahead
Phase 2 · On the day
Under a minute at the clinic
Phase 3 · After
Cytology and HPV result
- 01
Before
Abstain from anal intercourse
For 24 hours before the sample to avoid contamination and mucosal disturbance.
- 02
Before
No lubricants pre-test
Lubricant residue interferes with cytology — avoid on the day of the test.
- 03
On the day
Dacron swab inserted
A slim Dacron swab is passed a short distance into the anal canal.
- 04
On the day
Rotated and withdrawn
The swab is rotated against the mucosa and withdrawn to collect cells across the transformation zone.
- 05
On the day
Sample placed in liquid medium
The swab head is agitated into a liquid-based cytology vial.
- 06
On the day
HPV co-test performed
The same specimen is used for HPV genotyping alongside cytology.
- 07
After
Cytology and HPV result
A written report from the reporting pathologist within 7–10 days.
Result turnaround: 7–10 days. Abnormal results: same-week HRA.
What it shows
The range of possible cytology results.
Cytology is graded using a Bethesda-style system, from normal through ASCUS, LSIL, ASC-H, HSIL and features suspicious for invasive disease. HPV genotyping runs alongside.
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Normal cytology
No cytological abnormality — routine surveillance interval applies.
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ASCUS (atypical squamous cells)
Atypical squamous cells of undetermined significance — usually triaged by HPV status.
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LSIL (low-grade lesion)
Low-grade squamous intraepithelial lesion — often HPV-driven, usually monitored.
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ASC-H (atypical, cannot exclude HSIL)
Atypical squamous cells where HSIL cannot be excluded — HRA is warranted.
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HSIL (high-grade lesion)
High-grade squamous intraepithelial lesion — the precursor lesion targeted by treatment.
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Suspicious for squamous cell carcinoma
Cytological features suggestive of invasive disease — urgent HRA and biopsy.
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HPV genotype detection
High-risk HPV genotypes (particularly HPV 16) sharpen risk stratification.
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Red flag: HSIL or SCC on cytology — urgent HRA and biopsy
These results are escalated for same-week high-resolution anoscopy and targeted biopsy.
Next steps
What happens after your result.
The pathway is stratified by result. Normal cytology returns to routine surveillance; abnormal cytology triggers HRA; confirmed HSIL is treated.
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Reassurance if normal
A normal cytology and negative HPV result is reassuring — routine screening interval applies.
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Repeat screening at 12 months
For high-risk groups (HIV, MSM, post-transplant), annual repeat screening is standard.
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High-resolution anoscopy (HRA)
The next step for any abnormal cytology — magnified inspection of the anal canal with acetic acid and Lugol’s iodine.
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Targeted biopsy under HRA
Any suspicious area under HRA is biopsied for histological confirmation.
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Treatment of HSIL
Ablation, imiquimod or excision — treatment strategy depends on lesion size, site and patient factors.
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Colorectal surgery referral
Referral to a colorectal surgeon if invasive disease is confirmed on biopsy.
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HPV vaccination if unvaccinated
HPV vaccination is offered if not previously received — it reduces recurrence risk after HSIL treatment.
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Multi-disciplinary team review
Complex or invasive cases are reviewed at MDT — pathology, colorectal, oncology and radiology together.
Our vetted London network
A small panel of clinics, we picked them.
Partners across central, north, west and south London. Introductions are made privately, once we understand your case.
Selection criteria
How we choose every clinic in our network.
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Clinicians experienced in anal cytology sampling and HPV co-testing
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Liquid-based cytology processed in an accredited cytopathology laboratory
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On-site or same-week high-resolution anoscopy (HRA) if cytology is abnormal
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Onward colorectal-surgery and oncology pathway for HSIL and invasive disease
Safety and eligibility
A quick, low-risk screening test.
The sample itself is painless. The practical points are about who is eligible, what to avoid beforehand, and how red-flag results are escalated.
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Painless and quick
Sampling takes under a minute — a slim swab, no anaesthesia, no recovery.
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No radiation
Cytology and HPV testing use a swab — no imaging, no radiation, no dye.
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Position on the couch
You lie on your left side with knees drawn up — that is the whole preparation.
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Abstain 24 hours beforehand
No anal intercourse for 24 hours pre-test to avoid contamination.
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No lubricants on the day
Lubricant residue interferes with cytology — avoid on the day of the sample.
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Red flags escalate to HRA
HSIL or SCC on cytology triggers same-week high-resolution anoscopy — not a routine repeat.
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A normal cytology is not a full clear
A normal cytology does not exclude a visible lesion — any anal mass warrants direct examination.
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HPV vaccination is complementary
Vaccination reduces new infection and recurrence risk but does not replace screening in high-risk groups.
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Bring prior results and HIV records
Previous cytology, HPV genotypes and CD4 trend materially sharpen interpretation.
Reading your report
An anal cytology report can look intimidating. It isn’t.
Whatever the finding, the report keeps to the same four parts.
A quiet reminder
The report is written for your doctor, not for you — and that’s normal.
If you would like us to talk you through it before your follow-up, just ask.
- 01 Header
Indication and risk group
Your details, the reason for screening, and the risk group (HIV, MSM, post-transplant, cervical HSIL history) that shapes interpretation.
- 02 Technique
Sampling and processing
How the sample was taken, the liquid-based medium used, and the HPV assay platform.
- 03 Findings
Cytology grade and HPV genotype
The Bethesda-style cytology grade (normal, ASCUS, LSIL, ASC-H, HSIL, SCC) alongside high-risk HPV genotypes detected.
- 04 Impression
The conclusion: read this first
The overall interpretation and the concrete next step — routine repeat, HPV surveillance, or urgent HRA.
Recognised by major UK insurers
Cover depends on your policy and clinic; we confirm with your insurer before booking.
Sources
Guidance and evidence base.
This guide reflects current BHIVA and IANS practice, informed by the ANCHOR trial and NHS cervical screening principles applied to anal screening.
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British HIV Association (BHIVA). Guidelines on anal cancer screening.
British HIV Association (BHIVA). Guidelines on anal cancer screening. -
IANS — International Anal Neoplasia Society. Practice guidelines.
IANS — International Anal Neoplasia Society. Practice guidelines. -
ANCHOR trial (Anal Cancer HSIL Outcomes Research). New England Journal of Medicine.
ANCHOR trial (Anal Cancer HSIL Outcomes Research). New England Journal of Medicine. -
NHS Cervical Screening Programme guidance — principles applied to anal screening.
NHS Cervical Screening Programme guidance — principles applied to anal screening.
Last reviewed 2026-07-30. Next review 2027-07-30. Reviewed by Pulse Atlas Editorial Board, .
Frequently asked
Everything we get asked about anal cytology.
Quick answers on eligibility, sampling, HPV co-testing, and what happens when cytology is abnormal.
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What does anal cytology screen for?
Anal high-grade squamous intraepithelial lesions (HSIL) and anal squamous cell carcinoma. HSIL is the precursor lesion — the ANCHOR trial showed that treating HSIL prevents progression to anal cancer.
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Who should have anal cytology screening?
The main high-risk groups are people living with HIV, men who have sex with men (MSM), post-transplant patients on immunosuppression, and anyone with a history of cervical or vulval HSIL. Screening is not currently offered to average-risk adults.
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How is the sample taken?
A slim Dacron swab is inserted a short distance into the anal canal, rotated against the mucosa to collect cells from the transformation zone, and withdrawn into a liquid-based cytology vial. It takes under a minute and is painless.
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What is HPV co-testing and why does it matter?
Co-testing means running HPV genotyping on the same sample as cytology. It increases sensitivity over cytology alone, particularly for HSIL, and helps triage borderline cytology results such as ASCUS.
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What happens if my cytology is abnormal?
Any abnormal cytology — ASCUS, LSIL, ASC-H, HSIL or SCC — triggers high-resolution anoscopy (HRA). HRA uses acetic acid and Lugol’s iodine under magnification to identify lesions, which are then biopsied for histological confirmation.
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How quickly will I get results?
Cytology and HPV results are typically issued together in a written report within 7–10 days. Abnormal results are flagged for same-week HRA where indicated.
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In practice, in London
The honest picture around anal cytology test screening in London
With anal cytology test screening, the London question is usually about report turnaround and the radiologist reading it — not whether the scan is available. Waiting lists on the NHS for anal cytology test screening vary widely by borough and by how the GP letter reads. Privately in London, we can normally offer a slot inside the same week, sometimes within 48 hours if there’s a cancellation. The difference isn’t clinical quality — the consultants are frequently the same faces you’d see on the NHS — it’s the calendar.
A private anal cytology test screening pathway in London usually looks like this: an initial consultation, any diagnostics booked at a nearby facility (most within Zone 1 or 2), and a written report sent to you and your GP within a few days. The consultants we work with hold NHS posts alongside their private lists, which keeps the standards consistent across both settings. For anal cytology test screening specifically, the difference between a routine report and a sub-speciality read is where private care earns its keep.
The value of going through a concierge for anal cytology test screening isn’t access — anyone with an insurer or a credit card can get a private appointment in London. The value is knowing which consultant reads this particular presentation best, which unit turns reports around fastest, and which pathway won’t hit a dead end if the findings point somewhere unexpected.