This screening test (Pap test) is not a diagnostic test (manual screening). An abnormal screening results means that patient will need to have other tests (simple and advance diagnostic test) to find out if cancer or pre-cancerous change is actually present.

Cytology is a branch of science that deals with the structure and function of cells. It is also a manual test done to diagnose cancer by looking at cells under the microscope.

Pap test or Pap smear is a procedure used to collect cells from the cervix for cervical cytology testing. There are 2 main ways to prepare samples so that they can be examined under a microscope in the laboratory.


         Cytology Specimen 

For about 50 years, all cervical cytology samples were handled this way and are relatively inexpensive but it does have some disadvantages. One of the problems with conventional cytology is that the cells smeared onto the slides are sometimes piled up on each other making it difficult for Pathologist to see abnormal cells through the microscope and most time health professional reports patients result as normal.


The most widely used system for describing Pap test results is The Bethesda System (TBS). This system was developed in 1988, and has been revised twice in 1991 and 2001.

2001 version (TBS) categories:

*          Negative for intraepithelial lesion or malignancy

*          Epithelial cell abnormalities

*          Other malignant neoplasms

Negative for intraepithelial lesion: means there are no signs of cancer or precancerous changes. Specimens in this category appear entirely normal. Others may have findings that are unrelated to cervical cancer; such as signs of infections (with yeast, herpes or trichomonas). Some cases may also show “reactive cellular changes”.

Epithelial cell abnormalities: The second category epithelial cell abnormalities, means that the cells of the lining layer of the cervix show changes that might be cancer or a precancerous condition.

Further divided into 4 categories

  1. Atypical Squamous Cells (ASCs); these are further divided into ASC – U and ASC- H.
  2. Low-grade Squamous Intraepithelial Lesions (SILs)
  3. High-grade Squamous Intraepithelial Lesions (SILs)
  4. Squamous cell carcinoma

1          Atypical Squamous Cells: This category includes atypical squamous cells of uncertain significance (ASC – US). This term is used when there are cells that look abnormal, but it is not possible to tell by looking at the cells under a microscope whether the cause is infection, irritation or precancerous. Most of the time, cells labeled ASC-US are not pre-cancer. Some doctors will recommend repeating the Pap test after several months. Some doctors use the HPV DNA test to help them decide the best plan. If a woman with ASC –US is infected with high-risk type of HPV, doctors are more inclined to do a colposcopy. If a high grade SIL is suspected, it is called ASC – H and colposcopy is recommended.

  1. Squamous intraepithelial Lesions (SILs): These abnormalities are divided into low grade SIL and High grade SILs. High grade SILs are more likely than low-grade SILs to go away without treatment. High-grade SILs are also more likely to develop into cancer if they are not treated. Treatment can cure all SILs and prevent true cancer from developing. The need for this is based on the results of the colposcopy.
  2. Squamous Cell Carcinoma: This result means that the woman is likely to have an invasive squamous cell cancer. Further testing will be done to be sure of the diagnosis before treatment can be planned.

*          ADENOCARCINOMA: Cancers of the glandular cells are reported as adenocarcinoma. The pathologist examining the cells can suggest whether the adenocarcinoma started in the endocervix, in uterus (endometrium) or elsewhere in the body.

*          ATYPICAL GLANDULAR CELLS: When the glandular cells do not look normal but have features that do not permit a clear decision as to whether they are cancerous, it is known as typical glandular cells. The patient will have more testing if a cervical cytology result shows atypical glandular cells. (DETAILED GUIDE: CERVICAL CANCER; AMERICAN CANCER SOCIETY).


 Several types of biopsies are used to diagnose precancer and cervical cancer. Following an abnormal pap test,  a colposcopy is performed.

 Colposcopy: If the symptoms suggest or the screening result shows abnormal cells patient will need to have a test called colposcopy.

Colposcope is an instrument with magnifying lenses (like binoculars) that will enable the doctor see the surface of the cervix closely and clearly. Then doctor may treat the cervix with a weak solution of Acetic Acid (similar to vinegar) to make abnormal areas easier to see.

Method: In this procedure the patient will lie on the examination table. A sterilize speculum will be placed in the vagina to help the doctor see the cervix. Colposcopy is not painful and has no side effects and can be done safely even if you are pregnant. If an abnormal area is seen on the cervix a biopsy will be done. For a biopsy, a small piece of tissue is removed from the area that looks abnormal. The sample is sent to the pathologist to look at under a microscope. A biopsy is the only way to tell for certain whether an abnormal area is  precancerous or invasive cancer.

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