The Papanicolaou test, commonly known as a Pap smear, is a medical screening procedure designed to examine cells collected from the cervix. It functions as a routine, preventative tool in gynecological healthcare to monitor the cellular health of the lower part of the uterus, which opens into the vagina. The goal of this screening is to identify subtle cellular changes before they develop into cervical cancer, allowing for early intervention.
Why the Pap Test is Performed
The Pap test is a screening tool, not a diagnostic one, used to check for abnormal cell growth, medically termed dysplasia, on the cervix. These cellular changes are often caused by certain high-risk types of the human papillomavirus (HPV), a common sexually transmitted infection.
By identifying these precancerous cells early, the Pap test plays a direct role in preventing the development of cervical cancer. Cervical cancer typically develops slowly over many years, allowing the screening to catch abnormal cells long before they become malignant. Screening programs using the Pap test have significantly reduced the incidence and mortality rates associated with this type of cancer globally.
Preparing for and Undergoing the Procedure
Proper preparation helps ensure the collected cell sample is clear and readable for analysis. Patients are advised to avoid douching, using vaginal medicines, spermicidal foams, jellies, or creams for at least 48 hours before the test. These products can obscure the cervical cells, potentially leading to an unsatisfactory result that requires a repeat procedure.
Timing the test outside of the menstrual period is also helpful, as heavy bleeding can interfere with the cell sample quality. The Pap test is usually performed during a routine pelvic examination. A healthcare provider first inserts a lubricated speculum into the vagina to visualize the cervix.
A small brush and a tiny spatula are then used to gently collect cells from the surface of the cervix, specifically from the transformation zone where most abnormal changes occur. The collected cells are immediately preserved and sent to a laboratory. The entire collection procedure is quick and may cause a feeling of slight pressure or mild cramping.
Understanding What the Results Mean
Pap test results fall into three main categories: negative, unsatisfactory, or abnormal. A “negative” or “normal” result (NILM) indicates that no abnormal cells were found, and the patient can follow routine screening schedules. An “unsatisfactory” result means the lab could not properly analyze the sample, necessitating a repeat test in a few months.
Abnormal Results
An “abnormal” result means that changes were observed in the cervical cells, but this rarely indicates cancer. The most common abnormal finding is Atypical Squamous Cells of Undetermined Significance (ASC-US), suggesting that the cells look slightly irregular. Low-Grade Squamous Intraepithelial Lesion (LSIL) is a more definite finding of mildly abnormal changes, which are often caused by HPV infection and frequently clear up on their own.
High-Grade Squamous Intraepithelial Lesion (HSIL) represents more moderate to severe cellular changes that have a greater potential to progress to cancer if left untreated. Abnormal results like HSIL, or persistent ASC-US or LSIL, typically lead to follow-up procedures, such as a colposcopy. During a colposcopy, a magnifying instrument is used to get a closer, detailed view of the cervix, and a small tissue sample, or biopsy, may be taken to confirm the extent of the cellular abnormality.
Recommended Screening Schedules
Screening guidelines outline when individuals should begin testing and how frequently they should be screened, primarily based on age and health history. For most people, the recommendation is to begin cervical cancer screening at age 21. From age 21 to 29, the Pap test alone is typically recommended every three years, provided results remain normal.
Starting at age 30, individuals have options for screening frequency, often involving the Pap test combined with testing for the human papillomavirus (HPV), known as co-testing. Co-testing allows for a longer screening interval, usually every five years, because the combination offers a more comprehensive assessment of risk. Alternatively, a Pap test alone every three years or primary HPV testing alone every five years may be acceptable.
Individuals with a history of abnormal Pap results, a weakened immune system, or other specific health concerns may require more frequent testing. Screening can usually stop after age 65 if the patient has a history of consistently normal results over the previous decade and no history of high-grade precancerous lesions.