A Pap smear is a routine screening procedure designed to detect precancerous changes and cervical cancer. During this test, cells are collected from the cervix, the lower part of the uterus, and examined under a microscope. An “abnormal” result indicates that cells on the cervix appear unusual or atypical. While concerning, it is a common occurrence and usually does not mean cancer. Most abnormal Pap smears are due to less serious issues.
Understanding What “Abnormal” Means
An “abnormal” Pap smear result encompasses various cellular changes, from minor to significant. These classifications help determine appropriate follow-up.
Atypical Squamous Cells of Undetermined Significance (ASC-US) means cells look abnormal, but the cause (infection, irritation, or precancerous changes) is unclear.
Low-grade Squamous Intraepithelial Lesion (LSIL) indicates mildly abnormal cell changes, often associated with HPV. High-grade Squamous Intraepithelial Lesion (HSIL) suggests more serious, likely precancerous changes. Atypical Glandular Cells (AGC) are unusual glandular cells, which can be more concerning and may indicate a problem higher in the uterus or cervix.
An “unsatisfactory” result means the sample was inadequate for evaluation, requiring a repeat test.
The Role of Human Papillomavirus (HPV)
Human Papillomavirus (HPV) is the most frequent cause of abnormal Pap smear results. This common viral infection spreads through skin-to-skin contact, often during sexual activity. There are numerous types of HPV, categorized as either high-risk or low-risk, based on their potential to cause cellular changes.
High-risk HPV types are those that can lead to cervical cell changes and, if persistent and untreated, may progress to cervical cancer. Low-risk HPV types cause warts and are not associated with cancer. While HPV infection is highly prevalent, affecting most sexually active individuals, most infections clear on their own without lasting cell changes.
Other Common Reasons for Abnormal Results
Beyond HPV, other factors can lead to an abnormal Pap smear result. Infections, such as yeast infections (candidiasis), bacterial vaginosis, or trichomoniasis, can cause inflammation and temporary changes in cervical cells, mimicking abnormalities. These infections are treatable and, once resolved, usually lead to normal Pap results.
General irritation or inflammation of the cervix, not necessarily caused by an infection, can also result in atypical cell appearances. Hormonal changes, particularly those experienced during menopause, can affect the cervical cells and sometimes lead to an abnormal reading. Benign cell changes, which are non-cancerous, can also appear unusual under a microscope.
Technical issues during the sample collection or laboratory processing can also contribute to an abnormal or unsatisfactory result. This might occur if there are not enough cells collected, or if the sample is obscured by blood or mucus. In such cases, a repeat Pap smear is typically recommended to obtain a clearer sample for analysis.
Serious Abnormalities and Next Steps
More serious abnormal Pap smear results often indicate precancerous changes, known as cervical dysplasia or Cervical Intraepithelial Neoplasia (CIN). CIN is graded from 1 to 3 based on the severity of cell abnormality and the extent of affected cervical tissue, with CIN 1 being mild and CIN 3 being severe. In rare instances, a Pap smear can detect cervical cancer, though this is uncommon with regular screenings.
Serious abnormalities are frequently treatable, especially when detected early. Next steps depend on the specific type and severity of the abnormal result. For minor abnormalities, a repeat Pap smear or HPV co-testing may be advised to monitor changes.
If more significant abnormalities are identified, a colposcopy is performed. This procedure involves using a magnifying instrument to examine the cervix more closely, sometimes with an acetic acid solution to highlight abnormal areas. During a colposcopy, a biopsy may be taken, which involves collecting a small tissue sample for microscopic analysis to confirm a diagnosis. If precancerous or cancerous cells are confirmed, treatment options include Loop Electrosurgical Excision Procedure (LEEP) or cryotherapy to remove or destroy abnormal tissue.