Pap Smear Results: What Do ASC-US, LSIL and HSIL Mean?
What do ASC-US, LSIL, and HSIL mean in a smear test result?
ASC-US, LSIL, and HSIL are cytological terms that describe cellular changes seen in a smear sample. These terms do not mean the same thing, and the same follow-up is not recommended for all of them. ASC-US refers to atypical squamous cells whose meaning is not fully determined; LSIL refers to low-grade squamous cell changes; and HSIL refers to suspicion of high-grade changes. An abnormal smear result alone does not diagnose cancer. However, HSIL, in particular, is a finding that should not be delayed in terms of evaluation. The CDC's HPV surveillance guidelines differentiate between cytological classification and tissue diagnosis made by biopsy.
Seeing unusual abbreviations in the report can be concerning. The first step is to evaluate the entire report, rather than drawing conclusions about the future from a single word. The HPV result, age, previous screenings, and any previous procedures all influence the next step. This article explains what the terms mean and what questions might be helpful in a consultation; it does not create a personalized follow-up schedule. It is helpful to show the entire report to your healthcare professional, rather than just a screenshot, to learn what to do regarding your results.
A smear test is a screening test; it is not the same as a biopsy.
A smear test is based on the examination of cells collected from the cervix. Cytology evaluates the appearance of these cells. A biopsy is the examination of a small piece of tissue and provides information about the arrangement of cells within the tissue. Therefore, a definitive tissue diagnosis cannot be directly derived from a smear result. When necessary, colposcopy and biopsy are used to clarify what the screening finding means. ACOG's information on abnormal screening results also explains further evaluation within this framework.
For example, a smear report stating a low-grade change doesn't guarantee that a biopsy will show the same grade. Similarly, the consistency between a seemingly normal area and a laboratory finding is evaluated by the physician. Different test results don't always mean there's a laboratory error; they may be examining different samples and characteristics. Asking "Is this result for a cell analysis or a tissue analysis?" during the consultation makes it easier to follow up without confusing the reports.
What does ASC-US mean in a smear test result?
ASC-US stands for “atypical squamous cells of undetermined significance.” The cells do not appear entirely normal, but the nature of the change cannot be definitively classified based solely on this sample. The NCI states that factors other than HPV, such as irritation and hormonal changes, can also affect the appearance of the cells. Therefore, ASC-US should not be interpreted as a direct diagnosis of cancer, a definite HPV infection, or a definite benign condition. The HPV result and previous examinations are important for follow-up.
Someone whose ASC-US report says "Uncertain" might interpret it as meaning nothing is known. In fact, this result helps plan subsequent testing or follow-up to reduce uncertainty. The physician should explain what additional information they need. If you have had a previous HPV test, share the date and type information. Simply using a treatment for discharge doesn't automatically mean the ASC-US result is relevant. Treating the symptoms and following up on the screening findings can serve separate purposes.
How are ASC-US and HPV positivity evaluated together?
If ASC-US shows a positive result for high-risk HPV, colposcopy may be necessary depending on previous results and age. However, a recent negative result from appropriate HPV-based screening or specific colposcopy findings may allow for follow-up with repeat testing in some individuals. A negative HPV ASC-US may be treated at a different risk level. The CDC's table summarizing ASCCP recommendations shows that the same cytology result can be managed differently depending on past results. Therefore, it is not accurate to state the same timeframe for every ASC-US.
It is helpful that the follow-up recommendation does not simply state "come for a check-up." Clarify which test will be performed, the approximate date, and who will evaluate the results. If you haven't had an HPV test, ask if it's necessary; don't compare your situation to someone else's test results. If further investigation is recommended, find out why. The word "inflammation" in a section of the report does not negate the cellular changes that will be considered in conjunction with HPV positivity. The decision should be made based on the complete set of results.
What does LSIL mean in a smear test result?
LSIL stands for low-grade squamous intraepithelial lesion. Low-grade cellular changes are seen in the smear sample; these findings are often associated with HPV. LSIL is not a diagnosis of cancer, but it requires appropriate monitoring. Options for repeat testing or colposcopy are evaluated based on the individual's age, HPV result, and history. ACOG and NCI state that a low-grade result does not eliminate the need to evaluate whether a more serious change is present.
The term "low-grade" is not a justification for ignoring the result. However, it also doesn't mean that immediate treatment of the cervix is necessary. The purpose of a follow-up appointment is sometimes to observe the course of the change over time, and sometimes to investigate whether there are any more advanced findings. You can find out which of these two purposes is more important when talking to your doctor. During follow-up, evaluating new results alongside previous reports is more meaningful than performing tests in isolation.
What does HSIL mean in a smear test result? Does it mean cancer?
HSIL stands for high-grade squamous intraepithelial lesion. It requires timely further evaluation as it indicates the possibility of more significant cellular changes. However, the presence of HSIL does not automatically mean a diagnosis of invasive cancer. Colposcopy, biopsy, and in some high-risk cases, diagnostic or therapeutic tissue removal may be considered. The appropriate course of action is determined by age, pregnancy status, HPV type, and prior medical history. Waiting for a routine screening appointment is not advisable for HSIL.
When you receive this result, mentioning HSIL when scheduling an appointment will help in developing an appropriate assessment plan. Prepare the required documents and contact your healthcare provider if there are any delays. It is not accurate to place your result into a stage based on researching cancer stages online; HSIL is not a staging result. During your consultation with your doctor, you can first discuss what is known, what information is still missing, and how the proposed procedure will complete this information. This way, uncertainty can be transformed into a concrete assessment plan.
Differences between ASC-US, LSIL, and HSIL
The table below compares cytology terms. It should not be used to choose a treatment or schedule a follow-up appointment on your own. Decisions cannot be made solely based on abbreviations, especially if the HPV result is unknown or if cervical cancer treatment has been previously received. Findings not included in the table, such as ASC-H or AGC, should also be evaluated.
| Conclusion | What does it tell us and why is it followed? |
|---|---|
| ASC-US | Cellular atypia of uncertain significance; HPV and past results guide the evaluation. |
| LSIL | Low-grade cellular changes are assessed for the possibility of more advanced findings and the need for follow-up. |
| HSIL | Suspicion of high-grade changes requires timely further investigation and treatment evaluation in the appropriate patient. |
| NILM | No lesions or findings suggestive of malignancy were observed in the sufficient samples examined; however, the HPV result remains important. |
| Insufficient example | The sample is insufficient for a reliable cytological interpretation; it cannot substitute for a normal result. |
These terms are not necessarily steps that are passed through in a specific order. It is not mandatory for a person to have ASC-US first, then LSIL, then HSIL. Therefore, a person should not automatically assume a new result is incorrect simply because their previous report did not contain a milder term. Similarly, a milder term in the next report does not mean that the entire follow-up is complete. The timing of the results, the nature of the sample, and any tissue diagnoses are all interpreted together.
Are LSIL and CIN 1, and HSIL and CIN 2–3 the same thing?
LSIL and HSIL, when used in smear reports, describe cytological classification. CIN, on the other hand, is a histological term that grades tissue changes in the cervix. Histological LSIL or HSIL may also be used in biopsy reports; in this case, it is particularly important to specify which sample the report pertains to. While there is a correlation between cytological LSIL and CIN 1, and cytological HSIL and CIN 2 or CIN 3, these cannot be automatically used interchangeably based on smear results. Tissue diagnosis is determined by pathological examination.
When a CIN report is obtained, it is read in conjunction with the previous smear. In cases such as "My smear is HSIL but my biopsy is a lower grade," the adequacy of the examination and the agreement of the findings are also evaluated. This does not mean choosing one report and ignoring the other. If necessary, the pathology assessment can be reviewed or additional investigations can be planned. The NHS colposcopy information explains that CIN grades are associated with different follow-up and treatment options. For a personal decision, it is necessary to understand the entire examination, not just the grade.
What to expect during a colposcopy and biopsy procedure?
During a colposcopic examination, the cervix is evaluated under magnification. Small samples may be taken from areas deemed necessary. Before the procedure, the reason for its recommendation, which samples may be taken, and how the results will be communicated should be explained. It is important to provide information about blood-thinning medications, the possibility of pregnancy, or previous procedures. Medications should not be stopped on their own; instructions regarding preparation should be obtained from the unit performing the procedure.
During the examination, it is possible to express any discomfort or anxiety and request a break. The possibility of bringing a companion to the appointment and privacy preferences can be inquired about beforehand. If a biopsy is taken, the time required for results varies depending on the laboratory; contact the unit if you do not receive news within the specified time. A vulvar biopsy involves taking a sample from the external genital area and is not the same procedure as a cervical biopsy. When evaluating reports, the area from which the sample was taken should also be correctly indicated.
When are LEEP and conization considered in the treatment of HSIL?
LEEP or conization are procedures that remove tissue from the cervix in appropriate situations. They can be for diagnostic or therapeutic purposes. The statement "HSIL is present" does not necessarily mean the same procedure is necessary for everyone. In selected high-risk, non-pregnant, and appropriately aged patients, excision without prior biopsy confirmation may be considered; this approach is not applicable to all HSIL outcomes. The ASCCP guidelines emphasize the importance of joint decision-making, especially when future pregnancy plans exist.
If a procedure is recommended, you can ask which finding is being treated, whether alternatives exist, and how the removed tissue will be examined. Details such as the extent of the procedure and the need for repetition will be determined on a case-by-case basis. A hysterectomy is not an automatic decision simply because an abnormal smear test is found. It is important to share your pregnancy plans during the consultation, not afterwards. If you don't understand the reasoning behind the recommendation, you can ask for further explanation or seek a second opinion with supporting documentation; this process should not indefinitely delay the necessary evaluation.
Do age, pregnancy, and immune status alter the monitoring plan?
Yes. Especially in individuals under 25, the management of some low-grade findings may differ from that in older age groups. This does not mean that high-grade findings should be disregarded at a young age. Colposcopic evaluation can also be performed during pregnancy; however, some sampling and treatment options may not be applied or may be timed differently. The ASCCP's pregnancy recommendations state that accelerated treatment should not be applied when cancer is not suspected, and that an approach appropriate to pregnancy should be chosen.
Immunosuppressive diseases, a history of organ transplantation, or medications used are also important in the evaluation. Do not disregard this information at your appointment. Your doctor can explain its meaning for the current result. Using an online algorithm for another age or health group to manage your own result can be misleading. Coordinating pregnancy monitoring with cervical evaluation makes it clearer when each check-up should be done.
Why is an HPV test requested after an abnormal smear?
A high-risk HPV result helps determine the next step in following certain cytological findings. A positive test result is also evaluated based on which type is detected. A negative HPV result does not negate further investigation in all types of abnormal cytology; high-grade findings or those involving different cell groups are of particular importance. When learning about cervical screening methods, attention should be paid to how these tests are interpreted together.
When someone sees both HPV and smear results, they might want to consider them two separate "good" or "bad" signs. Clinical decisions are not made based on such a simple sum. The combination of findings, past results, and individual circumstances are evaluated. If an HPV test was performed but the type is not specified in the report, a full laboratory report may be requested. Knowing only that the test is positive may be insufficient for some decisions. Asking what information changes the plan helps understand the evaluation without resorting to unnecessary testing.
When should a repeat smear and HPV test be done during follow-up?
The follow-up interval varies depending on the current result, HPV, previous examinations, and any treatment. Low-risk surveillance is not the same as follow-up after treatment for high-grade lesions. The 2023 update of the ASCCP further clarifies the sequence of HPV-based follow-ups after treatment. Therefore, the routine screening interval for the general population should not be used as the follow-up date after an abnormal result. The routine screening program in Türkiye and individual follow-up for abnormal results are also distinct.
Before leaving the appointment, note the name and date of your next test. If it simply says “check-up in six months,” find out if this is a physical examination, smear, HPV test, or colposcopy. Not receiving the results doesn't automatically mean it's normal; contact them if you don't receive a response within the specified time. If the check-up was missed, you should reapply with the latest report to create an updated schedule. Specifically mention if a previously recommended colposcopy wasn't performed; a single normal test result in the intervening period doesn't invalidate the previous recommendation in any case.
If there is bleeding or pain when an abnormal smear is found
Post-coital bleeding, irregular bleeding, or postmenopausal bleeding require separate clinical evaluation. These symptoms should not be attributed solely to the smear test result, and a scheduled screening check-up should not be awaited. Complaints such as pain during sexual intercourse can also have different causes. If there is very heavy bleeding, fainting, or severe pain, an urgent evaluation should be sought. The screening report does not replace the symptoms experienced by the individual on that day.
The application should include a description of the time and amount of bleeding, and its connection to intercourse. The date of the last menstrual period, the possibility of pregnancy, and medications used should also be shared. A previous normal smear test does not rule out a new symptom. Similarly, an abnormal smear report does not indicate that all symptoms are caused by a malignant condition. The goal is to appropriately investigate the symptom and manage it in conjunction with the existing screening plan. These two assessments complement each other.
Can the HPV vaccine correct an abnormal smear result?
The HPV vaccine is not a treatment for existing cellular changes. It may be considered for protection against other HPV types in suitable individuals. Seeking advice about the HPV vaccine should not lead to delaying a recommended colposcopy or screening test. The CDC's vaccine recommendations separate prevention from treatment. The decision to vaccinate is based on previous doses, age, and individual circumstances.
Similarly, using vitamins, supplements, or vaginal products does not replace proper monitoring of cellular changes. Informing your doctor about the products you are using allows for the assessment of potential interactions. When considering treatment for HPV-related lesions , ask which finding is being targeted. You don't need to feel pressured to buy a specific product to improve your test results. Monitoring is based on confirmed findings, personal risk assessment, and appropriate action when necessary.
Information to bring to the appointment about your Pap smear result
All smear and HPV reports, previous colposcopy and pathology documents, cervical procedures, and medication lists can be prepared. You can group your questions under a few headings: What cell group does the result indicate? Is the HPV information sufficient? Why is further investigation recommended? When is the next follow-up? If it is difficult to remember what is said due to anxiety, taking notes or asking a close relative to attend the consultation may be helpful. You decide with whom your personal information is shared.
You can bring your reports with you when you apply for an evaluation with Assoc. Prof. Dr. Nazlı Korkmaz. The medical framework of this text utilizes information from the CDC, ACOG, NCI, NHS colposcopy guidelines, the ASCCP 2019 risk-based guidelines (2023 update), and pregnancy recommendations. The NCI's explanation of HPV and Pap results is an additional resource for understanding the terminology. A personal decision is made based on the complete report and examination evaluation; the online explanation alone does not determine treatment.
Frequently Asked Questions
Does ASC-US mean cancer?
No. It indicates atypia in the cells whose meaning cannot be precisely determined. It is evaluated based on HPV and previous results.
Does LSIL necessarily transform into HSIL?
No. These categories are not stages that everyone must pass through in sequence. However, the recommended follow-up should be continued.
Does an HSIL result definitively indicate cervical cancer?
No, but it requires timely further evaluation due to the high probability of a significant change.
If HPV is negative, does HSIL become irrelevant?
No. High-grade cytology, even if HPV negative, requires expert evaluation.
Are CIN 1 and smear LSIL the same report?
No. A smear is cytology; CIN is a grading system related to tissue analysis. The type of sample and the context of the report are important.
Does every abnormal smear require surgery?
No. The decision for repeat testing, colposcopy, biopsy, or treatment in the appropriate patient is made based on individual risks.
Is an abnormal Pap smear evaluated during pregnancy?
Yes. A pregnancy-appropriate examination and monitoring plan is devised; all procedures are not performed in a manner unrelated to pregnancy.
What should I do if I missed the check-up date?
Resubmit your reports and create an updated plan. Be sure to specify any previously suggested but not completed reviews.