A Pap test (cervical cytology) examines cervical cells collected during a pelvic exam under a microscope. The pathologist reports the appearance of those cells using a standardized classification system. The terms used — NILM, ASCUS, LSIL, HSIL, ASC-H — describe the degree of cellular change seen, from normal through progressively more abnormal. They do not describe cancer. They describe where the cells fall on the spectrum of normal to abnormal.
The key clinical point is that the spectrum from ASCUS to HSIL describes pre-invasive changes — changes in cervical cells that precede cancer, not cancer itself. The entire purpose of the screening and evaluation system is to identify these changes before cancer develops and either monitor them while they resolve on their own, or treat them before they can progress. When your Pap test finds an abnormality, it is doing exactly what it is designed to do.
NILM — Negative for Intraepithelial Lesion or Malignancy (Normal)
NILM is a normal Pap result. The cervical cells appear normal under the microscope. No abnormal cells were identified. This is the result the vast majority of women receive. A normal Pap result means you are due for your next screening at the interval recommended for your age group — no additional follow-up is needed.
ASCUS — Atypical Squamous Cells of Undetermined Significance
ASCUS is the most common abnormal Pap result. It means the pathologist saw some cervical cells that look slightly different from normal but not clearly abnormal enough to classify as a definitive lesion. ASCUS is a borderline finding — it can reflect mild HPV-related changes, inflammation, hormonal effects, or simply normal cell variation. Management of ASCUS depends on the HPV result: ASCUS with a negative HPV test is managed with routine repeat co-testing in 3 years. ASCUS with a positive high-risk HPV test proceeds to colposcopy. The risk of ASCUS representing high-grade dysplasia or cancer is very low.
LSIL — Low-Grade Squamous Intraepithelial Lesion
LSIL reflects more clearly abnormal cells than ASCUS, consistent with changes caused by HPV. It corresponds histologically to CIN 1 (mild dysplasia). Most LSIL results reflect active but transient HPV infections that the immune system will clear within one to two years. Management of LSIL in women 25 and older proceeds to colposcopy. In women under 25, observation with repeat testing is often preferred because high-grade dysplasia and cancer are extremely rare in this age group and most LSIL resolves without treatment. LSIL rarely represents high-grade dysplasia and almost never represents invasive cancer.
HSIL — High-Grade Squamous Intraepithelial Lesion
HSIL represents more significant cellular changes that correspond histologically to CIN 2 or CIN 3. HSIL warrants prompt colposcopy because high-grade dysplasia, if untreated, has a meaningful probability of progressing to invasive cancer over years to decades. However, HSIL on a Pap test does not mean cancer is already present — it means the cells appear significantly abnormal and require histologic evaluation to characterize the degree of dysplasia precisely and determine whether treatment is indicated. Colposcopy with biopsy provides the definitive diagnosis. Learn about colposcopy →
ASC-H — Atypical Squamous Cells, Cannot Exclude HSIL
ASC-H describes atypical cells where the pathologist cannot rule out that some cells may represent high-grade changes, even though the full criteria for HSIL are not met. ASC-H is managed the same as HSIL — with prompt colposcopy — because the possibility of high-grade dysplasia must be specifically evaluated.
AGC — Atypical Glandular Cells
AGC is a less common result reflecting abnormality in the glandular cells of the cervix rather than the squamous cells that most Pap abnormalities involve. AGC warrants more thorough evaluation including colposcopy with endocervical sampling, and in some women endometrial sampling, because glandular cell abnormalities can reflect changes from the cervical canal, the uterine lining, or other sources. AGC results are managed differently from squamous cell abnormalities and are discussed specifically at the follow-up visit.
The recommended timing of follow-up depends on the result:
- ASCUS with negative HPV: Repeat co-testing in 3 years — no urgent follow-up needed
- ASCUS with positive HPV, or LSIL: Colposcopy within 3 to 6 months
- HSIL or ASC-H: Colposcopy within 4 to 6 weeks — prompt follow-up is important
- AGC: Evaluation within 4 to 6 weeks with colposcopy and possible endometrial sampling
The most important thing to understand about an abnormal Pap result is that it reflects the screening system catching a change early — not a cancer diagnosis. For every woman who receives an HSIL result that leads to LEEP treatment, hundreds of women receive ASCUS or LSIL results that are managed with repeat testing as the cellular changes resolve on their own. The whole point of cervical cancer screening is to identify changes on the far early side of the spectrum that can be monitored or easily treated, preventing cancer from developing at all.
Dr. Ramona D. Andrei and the team at Lapeer Women’s Health are here to explain your specific result, provide the recommended follow-up, and guide you through the cervical health pathway with clear communication at every step — at both our Lapeer and Rochester Hills offices, without a referral required.
Our team at Lapeer Women’s Health provides result interpretation and all follow-up care at both offices. No referral required.
Schedule a Gynecologic VisitEducational purposes only. Not medical advice. Content reviewed by Dr. Ramona D. Andrei, MD PhD FACOG.
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Rochester Hills, MI 48307
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