When a lab tech or cytologist analyzes the sample of cells that was brushed from your cervix during Pap testing, they look for evidence of certain changes at the cellular level (cervical dysplasia). These changes exhibit various distinct microscopic features that the microscopist can then classify according to the Bethesda system. Each category within the Bethesda system (e.g., ASCUS) signifies a level of risk, and your healthcare practitioner will base their management strategy on a standard of care implied by that category.

Should you ever receive a phone call about an abnormal Pap smear result, you will want to know what that result really means. We hope this information will help you put things into perspective and understand any recommendations that may follow from your healthcare provider.

The following is a brief summary of terms and acronyms commonly used to categorize Pap results.

Normal Pap smear

A normal Pap smear reading means that there are no cell lesions or malignancy noted. Note that although Pap smears are a very good tool, they are not perfect — and false negatives do occur, which is yet another good reason to get regular screening. Other changes that can be present on an otherwise normal Pap smear include reactive cellular changes, cellular atrophy, and endometrial cells present.

ASCUS

ASCUS is a relatively common abnormal Pap test result indicating “atypical cells of undetermined significance.” This is a slightly irregular reading. Adding HPV testing is the current standard of care guiding the follow-up process. If your reading is ASCUS and negative for high-risk HPV strains, then repeat Pap testing is usually ordered at more frequent intervals for a while to monitor your immune response, with the hope that you will be able to heal any of the abnormal cells. If your reading is ASCUS and positive for high-risk HPV strains, then you will need to have a colposcopy for proper diagnosis.

LGSIL

LGSIL, the next grade of cellular abnormality, designates a “low–grade squamous intraepithelial lesion.” This low–grade lesion is seen as an indication that a high-grade HPV viral strain is likely causing abnormal cell features. This usually leads directly to colposcopic evaluation as the standard of care. Young healthy women are very likely to clear this degree of a problem — about 60% of them do. When an older woman’s Pap test is noted to have this degree of abnormality, however, it may be of higher concern, and she will definitely require close monitoring after the initial colposcopy.

HGSIL

HGSIL indicates a “high–grade intraepithelial lesion” and is of greater concern, as the HPV virus is likely to be causing moderate to severe changes of the cervix. Again, colposcopic biopsy of the cervix is warranted to clarify what is really there. Biopsy will provide a truer diagnosis, affording your practitioner the information they need to develop a plan for further monitoring or intervention.

AGUS

The term AGUS signifies “atypical glandular cells of undetermined significance.” Atypical glandular cells can originate from either the cervical canal or the uterus, and glandular lesions are more subtle and difficult to detect on cursory colposcopy, so a colposcopy and/or endometrial biopsy with additional biopsying may be required for a definitive diagnosis. It is not yet clear if HPV testing is of any significance for this category. In addition, AGUS is a relatively new classification, so management protocol with this category continues to evolve. For more information, see the ASCCP guidelines.

Endometrial cells present

A reading of “endometrial cells present” is of some concern for post menopausal women as it can reflect a build-up of endometrial cells inside the uterus, trickling down to the cervix and noted on Pap. This overabundance can be the result of higher–grade abnormal cells in a location other than the cervix — for example, the uterus. In this case, endometrial biopsy is the next step to provide a more definitive diagnosis and management strategy. In the years prior to menopause, however, the presence of endometrial cells can sometimes be correlated with simply having had the Pap test performed toward the end of your menses, so your practitioner will take into account the date of your last menstrual period when determining the need for further follow-up.

Remember, if you do receive the news that your Pap test results are abnormal or you have HPV, it doesn’t necessarily mean you will get genital warts; it doesn’t necessarily mean that your partner has been unfaithful; and only in the rarest of cases does it mean cancer. We are fortunate that in this day and age, we know more about what changes do mean at a cellular level, so we can monitor and treat them appropriately. So following up with your healthcare provider’s recommendations is truly important. Equally important, though, is that you are able to see an abnormal Pap as a call to take better care of yourself — on all levels.

For more information, read our full article on abnormal Pap smears and HPV, including seven ways to protect your reproductive health.