Pap Smear Report: NILM, ASCUS, LSIL and HSIL in Plain Words

The short answer: NILM on a Pap smear report means no abnormal cells were seen, ASCUS and LSIL usually mean mild changes that are rechecked or tested for HPV, and HSIL means stronger changes that need a closer look called colposcopy. None of these words is a cancer diagnosis on its own. Below, each term is decoded in plain words, with what normally happens next.

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You open the envelope. Capital letters. It reads like a code, and a worried mind fills the gap with the worst word it knows. Take a breath. The Bethesda System is simply the shared language that pathologists everywhere use to describe cervical cells, so that a report written in a lab in Lahore means exactly the same thing to a gynaecologist in Delhi, Dubai or London. Once you know the handful of terms, the Pap smear report makes sense.

What a Pap smear actually checks, ELI5

The cervix is the narrow doorway between the vagina and the womb. Its surface is lined with thin, flat cells, a bit like tiles on a floor. A Pap smear brushes off a few of those tiles. A lab checks them.

Healthy tiles look neat. Even. When the human papillomavirus (HPV) settles in, some tiles start to look odd: bigger centres, uneven shapes. Most of the time the body’s defences clear HPV within a year or two without any help, and the tiles quietly go back to looking normal, which is why so many mild results never become anything at all. Occasionally the changes stay for years and slowly get more serious, and catching them at that early stage, long before anything turns into cancer and while a small outpatient procedure can remove them completely, is the whole point of the test.

So it’s a screen. It looks for early warning changes in women who feel fine. It is not a test for infections like thrush, and it doesn’t check the ovaries or the womb lining.

How to read the Pap smear report, section by section

Most reports have three parts. Here is what each means.

1. Specimen type: “conventional” (smeared on glass) or “liquid-based” (cells rinsed into a small vial). Liquid-based samples can also be tested for HPV.
2. Specimen adequacy: “satisfactory for evaluation” is what you want. “Transformation zone present” means the sample reached the area where changes usually begin. “Unsatisfactory” means the lab couldn’t read enough cells, often because of blood or mucus, and the test is repeated, usually after 2 to 4 months.
3. General category and interpretation: this is the line with NILM, ASCUS and the rest.
4. Other findings: notes like “inflammation”, “Candida”, “bacterial vaginosis pattern” or “atrophic changes”. These are extra observations, not cancer findings.
5. HPV result (if done): positive or negative for high-risk HPV, sometimes naming types 16 and 18 separately.

The Bethesda terms in plain words

NILM: negative, and what “inflammation” means

NILM is a normal result. Many NILM reports also mention “inflammatory changes.” That phrase alarms people, but it’s very common and usually means mild irritation, a recent infection or just a normal reaction; it isn’t an early stage of anything. If you also have itching, smell or unusual discharge, that deserves its own check, and our guide to white discharge and when to see a doctor walks through the difference between normal and infection.

ASCUS: the grey zone

ASCUS stands for atypical squamous cells of undetermined significance. The cells look a little off. Why? Unclear. Infection, low hormone levels after menopause, or HPV can all do it. The usual next step is an HPV test on the same sample. HPV negative? Back to routine. HPV positive? The doctor usually suggests colposcopy or a repeat test.

LSIL: mild changes, usually from HPV

LSIL is a low-grade squamous intraepithelial lesion. It means HPV has caused mild changes. In young women these very often clear on their own over a year or two, which is why the doctor may simply repeat tests rather than rush to treatment.

HSIL: take it seriously, but it isn’t cancer

HSIL, a high-grade lesion, means the changes are more marked and less likely to settle alone. It is still a pre-cancer finding, not cancer. The next step is colposcopy, where a doctor looks at the cervix with a magnifier and may take a tiny biopsy. If the biopsy confirms high-grade change, a short procedure removes the affected area, and follow-up tests continue for some years.

How HPV testing links to your Pap result

HPV is extremely common and spreads through sexual contact, so most adults meet it at some point in their lives and clear it without ever knowing they had it, because it usually causes no symptoms at all. Only a few “high-risk” types, especially 16 and 18, cause most cervical cancers when they linger.

Many countries now use the HPV test as the main screening test, with the Pap smear as a follow-up if HPV is found. That’s why your report may show both. A negative HPV result is very reassuring, and it’s the reason screening intervals can be longer when HPV testing is used. The HPV vaccine protects against the types that cause most cancers; it works best before any exposure, but adults should ask their doctor whether it still makes sense for them.

How to prepare so the sample reads well

• Book it for a day when you are not on your period; mid-cycle is ideal.
• For 48 hours before, avoid intercourse, douching, vaginal creams, pessaries and lubricants, because they can wash away or hide cells.
• Tell the doctor if you’re pregnant, recently delivered, past menopause or have had a hysterectomy.
• Bring your previous reports. Change over time matters more than one result.

The test takes a few minutes. It can feel uncomfortable but shouldn’t be very painful, and you are always allowed to ask for a smaller speculum, ask the doctor to pause, or bring a female relative into the room if that helps you relax.

Pap smear report questions people ask

More guides that explain reports line by line are collected in Lab Reports Decoded.