An abnormal result from a Papanicolaou (Pap) test often leads to concern and many questions about what this finding truly signifies. The Pap test is a preventive screening method used to detect subtle changes in the cells of the cervix, the lower part of the uterus that opens into the vagina. By collecting a small sample of cervical cells, the test can identify abnormalities that, if left unaddressed, could potentially develop into cervical cancer over a period of years. Understanding that an abnormal Pap test is a screening finding, not a diagnosis of cancer, is the first step toward managing the result.
Understanding Pap Test Result Categories
When a Pap test is reported as abnormal, it means that the cells collected from the cervix appear different from healthy, normal cells when examined under a microscope. These cellular changes are clinically categorized based on the degree of abnormality observed, which helps guide the next steps for follow-up. The mildest and most common abnormal finding is Atypical Squamous Cells of Undetermined Significance (ASC-US). This result means the cells look slightly irregular, but the cause cannot be definitively determined.
The next step up in severity is Low-grade Squamous Intraepithelial Lesion (LSIL), which indicates mild dysplasia or minor cell changes typically caused by a human papillomavirus (HPV) infection. The more significant category is High-grade Squamous Intraepithelial Lesion (HSIL), representing moderate to severe cell changes that have a higher probability of progressing to cancer if not treated. A separate category is Atypical Glandular Cells (AGC), which refers to abnormal cells originating from the mucus-producing glands of the cervix or uterus and generally requires a more extensive evaluation.
The Link Between Abnormal Cells and HPV Infection
The direct answer to whether an abnormal Pap test means HPV is nuanced: the Human Papillomavirus is the overwhelming cause of most abnormal squamous cell changes. HPV is a very common sexually transmitted infection, and most sexually active individuals will contract it at some point. The virus infects the skin cells of the cervix, causing them to change and become abnormal, a condition known as cervical dysplasia.
However, HPV is not the sole cause; other factors, such as benign infections (like yeast or bacterial infections), inflammation, or natural hormone changes related to menopause, can sometimes result in mildly abnormal Pap test results like ASC-US. Furthermore, there are over 100 strains of HPV, which are divided into low-risk and high-risk types. Low-risk types typically cause minor changes or genital warts, while persistent infection with high-risk types is what leads to the precancerous changes seen in HSIL and ultimately, cervical cancer.
Most HPV infections are transient, meaning the body’s immune system clears the virus naturally, often within 12 to 24 months, and the cervical cells return to normal without intervention. The concern arises when a high-risk HPV infection persists, continually causing cellular damage, which is why regular screening and follow-up are necessary to catch these persistent changes.
Immediate Follow-up Procedures
Following an abnormal Pap test result, the immediate next steps are determined by the specific category of the abnormality and often involve further diagnostic testing. For the mildest result, ASC-US, a reflex HPV test is typically performed on the same collected sample to determine if a high-risk HPV type is present. If the HPV test is negative, the patient usually returns to routine screening because the risk is very low. If the HPV test is positive, or if the initial Pap result was LSIL, HSIL, or AGC, a procedure called a colposcopy is generally recommended.
A colposcopy is a magnified examination of the cervix that is performed in the office. During this procedure, a mild acetic acid solution is applied to the cervix, which helps to highlight any abnormal areas by turning them white. The clinician uses a specialized magnifying instrument, the colposcope, to closely inspect the cervical surface. If any suspicious tissue is observed, a small tissue sample, known as a biopsy, is taken for analysis to determine the precise degree of cell change.
Managing Confirmed High-Risk Cell Changes
The management strategy for high-risk cell changes is based on the results of the colposcopy and biopsy, which categorize the changes as cervical intraepithelial neoplasia (CIN). CIN 1 represents the mildest changes, often corresponding to LSIL, and these are frequently managed with active monitoring, such as a repeat Pap and HPV co-test in 6 to 12 months, as CIN 1 can regress naturally. If the biopsy confirms moderate or severe cell changes (CIN 2 or CIN 3, corresponding to HSIL), intervention is typically required to remove the abnormal tissue and prevent progression to cancer.
The most common therapeutic procedure for removing precancerous cells is the Loop Electrosurgical Excision Procedure (LEEP), which is an in-office treatment. LEEP uses a thin, electrically charged wire loop to excise the abnormal tissue from the cervix, offering both treatment and a final tissue sample for diagnosis. An alternative ablative method is cryotherapy, which destroys the abnormal cells by freezing them. Following these interventions, patients enter a phase of close follow-up with regular co-testing to ensure the abnormal cells and high-risk HPV infection have been successfully eradicated.