Cervical Cytology
Cervical cytology is used to analyze and study exfoliated cells from the endocervix and ectocervix, which is essential to increase the sensitivity of the Pap test. It is the method of choice for detecting cervical cancer. Its use has reduced the incidence and mortality from cervical cancer.
Currently in Mexico, the Pap test is the gold standard for cervical cytology. Its success as a screening method for cervical cancer detection is due to its relative simplicity and low cost of the test.
Sample Preparation
Cells are obtained from the outer surface of the cervix (ectocervix) and cervical canal (endocervix) to evaluate the transformation zone (squamous junction), the area at highest risk for neoplasia.
Basic material for the procedure:
- Letterhead slide with patient data
- Wooden Ayre spatula, cytological brush, and/or cytological brush
- Vaginal Mirror
- Gloves
- Face mask
- Cytological fixative (cytospray)
- Saline Solution
- Examination table
- Lamp
- May table
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Cytological Devices |
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DEVICE |
GUY |
ADVANTAGES |
DISADVANTAGES |
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Ayre's spatula |
Wooden spatula |
Economical, easy to use. Takes samples from the endo and ectocervix |
Cells trapped in wood |
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Cytological brush |
Nylon fiber brush |
Penetrates the canal, does not trap cells, malleable fibers allow insertion into the canal. Nylon prevents cells from sticking, rigid fibers can penetrate the gland |
Stiff fibers can be traumatic and cause pain. The metal wire can theoretically puncture the yolk sac. |
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Cytological Brush |
Rubber brush parallel to the handle and located at its tip. The central fibers are longer to facilitate endocervical sampling. |
Simultaneously takes samples from the ecto and endocervix |
High cost |
Taking the cytological sample
The ectocervix sample should be taken first, since taking the endocervical sample frequently causes bleeding that contaminates the ectocervical sample, making diagnosis difficult.
- Ayre's spatula
To obtain a sample from the ectocervix, the modified Ayre spatula is introduced by the forked end, placed in the orifice and turned 360◦ to the right while applying light pressure.
The spatula is reintroduced by the pointed end into the endocervical canal, sliding and turning to the left 360◦ with light pressure.
The Ayre Spatula was designed by Dr. J. Ernest Ayre and is shaped like the upper end of the femur, so that its prominence and angle fit into the endocervical orifice and ectocervix to obtain material from the transformation zone.
This device is useful when the transformation zone is located in the external vicinity of the cervical orifice and the curvatures of the device and the cervix coincide.
- Cytobrush
It should only be used when the transformation zone is not visible, such as in postmenopausal patients or in women previously treated with conization or another type of treatment. “It should not be used in pregnant women.”
It is straight and cylindrical; to obtain the sample, at least three-quarters of the brush must be introduced into the endocervical canal and rotated 90◦. Over-rotation can cause distortion in the cells, as well as bleeding, which makes the interpretation of the smear difficult.
It is effective when the transformation zone is around a small round hole, or where the transformation zone, which is located towards the endocervical canal, cannot be seen, as would be the case in a cervix with atrophy.
It is recommended and has been proven to use two devices, one for the ectocervix (spatula) and another for the endocervix (cytological brush), and to perform the two samples separately.
- Cytological brush (cervical brush)
It is made up of flexible rubber bristles in the shape of a gable roof, with the longest bristles in the center, which are the ones that enter the cervical orifice, and the shortest ones on the periphery, which remain on the outside.
The device is manipulated by inserting the longer bristles into the hole and rotating it 360° three to four times. The rotation is stopped if there is bleeding. As it rotates, it “sweeps” the entire contact site, which is generally wide. This would appear to be the ideal device; however, in small holes, the bristles do not enter the canal, in cervixes with wide ectropion, and in very long holes, material from the transformation zone is not obtained. The cytological brush is the best option for pregnant women or those with a cervix that bleeds easily.
Regardless of the device used, all samples obtained from the cervix should be spread on the slide, not rubbed. They should be immediately fixed with cytological fixative spray (cytological spray/cytospray), at a distance of 20 cm for 5 seconds.
Sampling Results
A cervical cytology should provide information on three basic components:
- Sample quality
- Categorization of results
- Interpretation and descriptive diagnosis of the findings
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