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Pap Smear Test

Last updated April 22, 2018

Approved by: Maulik P. Purohit MD, MPH

Periodic Pap screening in women, beginning from age 21 years, helps in early detection of any abnormal cells in the cervix; thus picking-up any pre-cancer or cancer, in the early stages itself.

What are the other Names for this Test? (Equivalent Terms)

  • Cervical Cytology Test
  • Cervical Smear Test
  • Papanicolaou Smear Test

What is Pap Smear Test? (Background Information)

  • A test that involves looking at individual cells under a microscope, in order to make a diagnosis, is called a cytological test. The Pap Smear Test is a cytological test that looks at cells from the cervix (the lower part of the uterus/womb), to screen for cervical pre-cancers, cancers, or any other possible infection
  • Cell samples are collected from the exo- (outer surface) and endo- (inner surface) cervix and prepared, via one of the two possible ways for examination:
    • Conventional cytology: The cell sample is smeared onto a slide directly and examined by a pathologist, under a microscope. Although this method is fast and inexpensive, it has some disadvantages, such as uneven spreading of cells on the slide and interference to reading due to mucus, white blood cells, and possible yeast or bacterial cells. Thus, if the slide cannot be read clearly/properly, the test may have to be repeated
    • Liquid based cytology: The cell sample is transferred into a liquid preservative and spread evenly onto a slide, with special instruments. Any interfering mucus, white blood cells, or bacteria, are also removed to an extent, during processing. This reduces the chance of requiring a repeat Pap Smear Test. HPV (human papilloma virus) testing may also be done on this sample. However, the liquid-based test is more expensive
  • The smear test may be reported as negative for any intraepithelial lesion, or any cellular abnormalities noted, may be mentioned
  • Periodic Pap screening in women, beginning from age 21 years, helps in early detection of any abnormal cells in the cervix; thus picking-up any pre-cancer or cancer, in the early stages itself

What are the Clinical Indications for performing the Pap Smear Test?

The Pap Smear Test is a screening test for cervical pre-cancers and cancers. It also helps in detecting cellular abnormalities in the cervix, which may be due to infections.

According to the American Cancer Society, the American College of Obstetricians and Gynecologists (ACOG), and the U.S. Preventive Services Task Force (USPSTF):

  • Pap smear screening should begin from age 21 years and not earlier
  • Between the ages of 21-30 years, the Pap Test should be conducted every 3 years
  • Between the ages of 30-65 years, Pap smear and HPV testing should be conducted every 5 years. It also acceptable to have just a Pap Test, every 3 years
  • After 65 years of age, screening may be discontinued:
    • If there is no history of cervical cancer
    • And the last 3 consecutive Pap smears, or last 2 consecutive HPV DNA testing (within the last 10 years; the most recent result of which, should be within 5 years) have been negative

Frequent testing is necessary for women at high risk of cervical cancer, such as:

  • Women with previous history of cervical pre-cancer or cancer
  • HIV positive individuals
  • Those with weakened immune systems

The physician may also order a Pap Smear Test, if he/she deems it necessary, to investigate women with:

  • Abnormal vaginal bleeding/discharge
  • Pain during intercourse
  • And/or with history of multiple sex partners

How is the Specimen Collected for Pap Smear Test?

Sample required: Cells from the cervix (cervical smear)

Process: For a Pap Test

  • The woman is instructed to lie on her back
  • The cervix is then visualized, by keeping the vagina open using a speculum
  • A spatula or a cervical brush is then used to collect cells from the endocervix (inside of the cervix)
  • A second sample is taken from the ectocervix (outside of the cervix)
  • The cell samples are then transferred onto a slide in the conventional method, or into a liquid preservative, in the liquid-based cytology method. Cells from the liquid preservative, after further handling/process, are then smeared onto a slide
  • Once the slide has been prepared, it is examined under a microscope by a pathologist and the results are reported

Preparation required: Instructions to be followed prior to Pap Smear Testing

  • Avoid having a vaginal douche or bathing in a tub, 24 hours prior to testing
  • Avoid sexual intercourse, 24-48 hours prior to testing
  • Avoid using vaginal creams, 48 hours prior to testing
  • It is advised to avoid scheduling a Pap smear during menses

What is the Significance of the Pap Smear Test Result?

The Pap Smear Test results are reported according to ‘The Bethesda System’ (TBS), 2001. It may be the following:

  • Unsatisfactory: This may occur due to an inadequate cell sample, or due to the presence of certain interfering substances
  • Negative for intraepithelial lesion (an abnormal cell growth on the cervix) or malignancy: Cells do not show any signs of pre-cancer/cancer. They may be normal, or may shows signs of infection
  • Atypical cells of uncertain significance: These include atypical squamous cells of uncertain significance (ASCUS) and atypical glandular cells of uncertain significance (AGCUS). These are abnormal looking cells, where the cause of the abnormality cannot be determined. These atypical cells prompt further testing
  • Squamous intraepithelial lesions (SIL): Depending on how abnormal the cells appear, they may be either of the two:
    • Low grade SIL (LSIL) - LSIL cells show mild abnormality
    • High grade SIL (HSIL) - HSIL cells are very atypical and are ‘highly likely’ to progress to cancer, if left untreated
  • Squamous cell carcinoma or adenocarcinoma: The cells are cancerous and are either flattened (squamous), or tall and column like (adenocarcinoma)

The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.

Additional and Relevant Useful Information:

  • The progression from pre-cancer to cancer of the cervix is a very slow, gradual process
  • The sample of cells, collected during the Pap Test is generally very small; hence, a single test is insufficient to pick up an abnormality that may be present. Due to this, periodic Pap Smear Testing is advised, in order to screen for cancers
  • Vaginal douches, creams, and drugs, such as digitalis and tetracycline, may affect the Pap smear results

The following article link will help you understand cervical cancer.


Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.

What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: March 4, 2014
Last updated: April 22, 2018