Pap test (cytology): how to take it, NILM, ASC-US, LSIL interpretation

In shortThe Pap test is cervical cytology: it looks for atypical cells before they become cancer. Answer categories: NILM — normal; ASC-US — unclear changes (the HPV test decides); LSIL/HSIL — changes requiring colposcopy. Screening for women from 21–25 or from the start of sexual activity — on the gynecologist’s schedule.

What this marker is

Cervical cancer develops over years through precancer stages, and the Pap test catches them early — that is why regular cytology sharply cuts mortality.

The modern answer system is Bethesda: NILM (normal), ASC-US (atypical cells of undetermined significance), LSIL (low-grade changes), HSIL (high-grade changes). The decision between observation and colposcopy is made together with the high-risk HPV test result.

Reference ranges

Group	Reference range
NILM	normal — no atypical cells; routine screening schedule
ASC-US	unclear cells — the plan depends on the HPV test
LSIL	low-grade changes — colposcopy or observation by age and HPV
HSIL	high-grade changes — colposcopy with biopsy is mandatory
AGC	atypical glandular cells — extended workup

A normal Pap test does not cancel the next scheduled one: screening works through regularity. Spotting between periods is a reason to see a doctor regardless of the last test date. Ranges differ between laboratories.

Check your value

Enter the number from your lab report — see how it compares with the typical range. Mind the units shown in the chosen row.

An approximate comparison with a typical range, not a diagnosis. Ranges differ between laboratories — use the one on your report; a doctor interprets the result.

When it is high or appears: possible causes

ASC-USMost often reactive changes from inflammation; with positive HPV — colposcopy.

LSILUsually a result of active HPV infection; in most young women it clears by itself — observation.

HSILA true precancerous change — colposcopy with biopsy and treatment are needed.

Inflammation in the smearInfection distorts the cells — treatment first, then cytology control.

What can skew the result

These factors can shift the result without any disease — keep them in mind before a retest:

MenstruationSuppositories and creams 1–2 days beforeIntercourse the day beforeRecent inflammation

How to prepare

Not during menstruation; no vaginal products, douching or intercourse for 1–2 days. Details: Preparation: swab.

When a retest makes sense

Normal — cytology every 3 years or HPV testing every 5 years (per local programs). ASC-US — control in 6–12 months or colposcopy by HPV status.

Who usually reviews this result

An out-of-range result is usually reviewed by: Gynecologist. Bring your report and any previous results to the visit.

Names used on lab reports

Look for one of these names on your report:
Pap testPap smearCytologyCervical cytology

Several markers on your report?

The app reads your whole report — this marker together with its neighbors, not one by one.

Get your results explained See an example

Frequently asked questions

ASC-US — is it cancer?

No: unclear cells most often relate to inflammation or HPV. The high-risk HPV test decides: negative — just a checkup in a year, positive — colposcopy.

From what age and how often?

Usually from 21–25 or from the start of sexual activity; the schedule is cytology every 3 years or HPV testing every 5 years per local guidelines and the gynecologist’s advice.

Is the Pap test painful?

No: a brush takes the smear from the cervical surface in seconds. Brief spotting afterwards is possible.

Sources

WHO — Guideline for screening and treatment of cervical pre-cancer lesions — WHO, 2021 (who.int). Accessed: September 17, 2026.
MedlinePlus — Vitamin A test — MedlinePlus (medlineplus.gov). Accessed: September 17, 2026.

Pap test (cervical cytology)