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Pap Smear

Also known as: PAP Test

Formal name: Papanicolaou smear; Cervical smear; Cervical/vaginal cytology

Related tests: Human Papillomavirus (HPV); Trichomonas wet prep

At a Glance

Why Get Tested?

To screen for cervical cancer and certain vaginal or uterine infections

When to Get Tested?

If you are a woman over the age of 21 and/or sexually active; once every 2 years or as advised by your doctor

Sample Required?

Cells from the cervical area

Test Preparation Needed?

You may be instructed not to douche or tub bathe for 24 hours before the Pap smear is to be performed. You may also be asked to refrain from sexual intercourse for 24 to 48 hours before the test. Do not use any vaginal creams or foams for 48 hours prior to the exam and do not schedule the test during your menstrual period.

The Test Sample

What is being tested?

A Pap smear is a test used to detect abnormal or potentially abnormal cells from the vagina and uterine cervix. It is a routine screening exam for women that can identify pre-cancerous changes and early, easily treatable cervical cancer. Various bacterial, fungal, and viral infections of the uterus may also be detected using this test.

How is the sample collected for testing?

The conventional method consists of sampling cells from the cervical area. The sample is obtained using a type of wooden “spatula,” cotton swab, or brush. Relatively new liquid-based methods are available that are modifications of the conventional Pap smear. The specimen is collected as noted above but is not placed directly onto a glass slide. Rather, it is put into a special liquid preservative. This cell suspension is processed onto a glass slide, stained, and examined.

Is any test preparation needed to ensure the quality of the sample?

You may be instructed not to douche or tub bathe for 24 hours before the Pap smear is to be performed. You may also be asked to refrain from sexual intercourse for 24 to 48 hours before the test. Do not use any vaginal creams or foams for 48 hours prior to the exam and do not schedule the test during your menstrual period.

How is it used?

Your doctor or health provider performs a Pap smear primarily to look for cervical and/or vaginal cells that are cancerous or could be potentially pre-cancerous. A sample of cervical cells or cell suspension is placed on a glass slide, stained with a special dye (Pap stain), and viewed under a microscope by a cytotechnologist or pathologist. The Pap test can also be used to detect vaginal or uterine infections. Abnormal cells and infections can be present without causing any noticeable symptoms. Some may require treatment while others may resolve on their own, prompt further testing, or be monitored over time. Some strains of human papillomavirus (HPV), a very common sexually transmitted viral infection, can be associated with an increased risk of cervical cancer. An HPV DNA test may be ordered along with or following a pap smear, especially for women over the age of 30.

When is it ordered?

The appropriate frequency of Pap testing is dependent on age and sexual activity. The American Congress of Obstetricians and Gynecologists (ACOG) revised their guidelines in 2009 to recommend that screening with Pap smears begin no earlier than age 21 and then be performed every two years until age 29. A Pap smear may not be required more than once every three years at 30 years of age and after, with three consecutive normal Pap smears and presence of no other abnormalities. ACOG also recommends that women 30 years of age or older be offered the option of having an HPV DNA test along with the Pap smear. If both are negative, testing should be performed no sooner than every three years.

If a woman has or has had a history of certain conditions, then a Pap smear may be done more often. Some of these conditions include:

  • HIV

  • Suppressed immune system, such as a transplant recipient

  • Her mother took DES (diethylstilbestrol) when pregnant with her

  • Previously treated for cancer or a condition called cervical intraepithelial neoplasia-2 or 3 (CIN 2, CIN 3)

In other situations, a Pap smear may be ordered when a woman has frequent sexual partners, is pregnant, or has abnormal vaginal bleeding, pain, sores, discharge, or itching.

What does the test result mean?

A "negative" Pap smear means the cells obtained appear normal or there is no identifiable infection. In some instances, the conventional Pap smear may be reported as "unsatisfactory" for evaluation. This may mean that cell collection was inadequate or that cells could not be clearly identified. A summary of other reported results follows.

  • Unsatisfactory: inadequate sampling or other interfering substance

  • Benign: non-cancerous cells, but smear shows infection, irritation, or normal cell repair

  • Atypical cells of uncertain significance: abnormal changes in the cells that cover most of the external part of the cervix (squamous cells-ASCUS) or in the cells that cover the lining of the uterus opening and canal (glandular cells—AGCUS) for which the cause is undetermined; an ASCUS test result is frequently followed up with DNA testing to identify the presence of a high-risk infection with HPV.

  • Low-Grade changes: frequently due to infection with HPV, which in some instances can be a risk for cervical cancer; this test result may be followed up with DNA testing to identify the presence of a high-risk HPV infection.

  • High-Grade changes: very atypical cells that may result in cancer

  • Squamous cell carcinoma or adenocarcinoma: terms used to identify certain types of cancer; in these cases, cancer is evident and requires immediate attention.

Is there anything else I should know?

The Pap smear is generally used as a screening test. A certain percentage of abnormalities in women may go undetected with a single Pap smear, which is why it is important to have Pap smears done regularly. A significant limitation of the test has to do with sample collection. The Pap smear represents a very small sample of cells present on the cervix and in the vaginal area. Even for the most experienced physician, sample collection can be occasionally inadequate and a repeat Pap may be required.

The Pap smear, when performed routinely, has been a great help in the detection and treatment of areas of pre-cancer, which helps prevent cervical cancer from developing. In addition, the test helps detect cervical cancer in the early stages, when it is most treatable. The Pap smear is also used to monitor any abnormalities or unusual findings. In many cases, these findings are part of the body's repair process and often resolve themselves without any further treatment. If you douche, tub-bathe, or use vaginal creams 48 to 72 hours prior to the examination, your test results might be "unsatisfactory." Other factors that may alter results include menstrual bleeding, infection, drugs (such as digitalis and tetracycline), or having sexual relations within 24 hours prior to examination.

In these cases, a repeat Pap smear may be necessary, but it does not necessarily mean there is a significant problem. In some instances, the use of the liquid-based techniques may eliminate obscuring materials such as blood and mucus that may prevent a clear and uncluttered presentation of cervical cells. A second advantage is that the same sample may be used to perform additional testing for HPV, if appropriate.

Common Questions

What are the risk factors for cervical cancer?

The most important risk factor for cervical cancer is infection with human papilloma virus (HPV). Tests are available to screen for this type of infection and are often performed in conjunction with a Pap smear. Also, a vaccine is available to help prevent HPV infection. It is given in three doses over a period of six months and is most effective if given before becoming sexually active.

Increased risk is also associated with the age at which sexual intercourse begins (the earlier, the higher the risk), multiple sexual partners, infrequent PAP smears, cigarette smoking, a medical history of DES exposure, and the presence of othersexually transmitted diseases such as herpes or HIV.

Does an abnormal Pap smear always mean cancer?

A single “abnormal” Pap smear does not necessarily indicate that cancer is present. The membranes covering the cervix undergo constant changes and repair. While treatment may not be necessary, the situation should be monitored closely. This may require a repeat Pap smear every three to six months until the situation is resolved.

If I have cervical cancer, what are my treatment options?

Cervical cancer is a slow, progressive disease and may take years to advance beyond the cervix. It is because of this fact that regular gynecologic examinations offer the best opportunity to prevent cancer from developing by allowing the detection and removal of pre-cancerous tissue. Regular exams can also detect this type of cancer early if it does develop. Minimally invasive surgery of the cervix (terms your physician may use are LEEP, conization, cold-knife, or cryotherapy), which removes pre-cancerous or very early stage cancer tissue, is the standard treatment.

In more advanced cervical cancers, a hysterectomy may be performed. If the cancer spreads to other tissues (metastasizes), radiation therapy may be required and, in some instances, additional surgery may be needed.

Content last reviewed in April 2009. | This page was last modified in July 2011.

Content by Lab Tests Online

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