How to Perform a Pap Smear
The optimal technique involves using either a cervical broom device (single collection) or the combination of an extended-tip spatula plus endocervical brush (dual collection), both of which adequately sample the transformation zone and squamocolumnar junction where precancerous changes occur 1.
Patient Preparation
Instruct patients to avoid the following for 48 hours before the test 1:
- Douching
- Intercourse
- Tampons
- Vaginal creams, foams, jellies, or medications
Schedule to avoid menses when possible, but do not defer if abnormal bleeding is present (intermenstrual, postcoital, or postmenopausal bleeding) 1.
If mucopurulent discharge is present, carefully remove it with a saline-soaked cotton swab before collecting the specimen—do not delay the test 2.
Collection Technique
Option 1: Cervical Broom (Single Device Method)
This is the preferred method for pregnant women and can be used for both conventional and liquid-based cytology 1:
- Insert the long central bristles into the endocervical os while pressing the broom against the cervix until the outer bristles bend
- Rotate in ONE direction only for 5 complete rotations (do not reverse direction, as this causes cell loss) 1
- For conventional cytology: Stroke the broom across a labeled glass slide from the frosted label margin toward the opposite end, then immediately fix with spray fixative or immerse in 95% ethanol 1
- For liquid-based cytology: Rinse the broom vigorously in preservative medium, or snap off the handle and leave the broom in the fixative vial 1
Option 2: Extended-Tip Spatula + Endocervical Brush (Dual Device Method)
This combination has the lowest false-negative rate compared to less thorough sampling 1:
- First, use the extended-tip spatula to sample the ectocervix and transformation zone with a circumferential scraping motion
- Then insert the endocervical brush into the canal until the bristles closest to the handle are approximately even with the external os
- Rotate the brush 180 degrees (one-half turn only)—additional rotation does not improve sampling and may cause bleeding 1
- For conventional cytology: Roll the brush sample onto a labeled glass slide adjacent to the frosted label (about 2 cm), then immediately smear the spatula sample adjacent to the brush sample using a circular motion. Fix rapidly with spray fixative or 95% ethanol 1
- For liquid-based cytology: Rinse both devices carefully in a single vial of preservative. Use a plastic spatula (not wood) as cells wash off more readily 1
Critical Technical Points
The specimen must include cells from the transformation zone and squamocolumnar junction—this is where most precancerous changes occur 1, 3, 4. Vaginal samples are not necessary and not recommended 1.
Immediate wet fixation is essential for conventional smears to prevent air-drying artifact 3, 4. The slide must be fixed within seconds of smearing.
Special Populations
Pregnant women: Use the cervical broom OR the combination of extended-tip spatula with a moistened cotton swab (not the endocervical brush, though there is considerable clinical experience using the brush without complications) 1, 2.
Post-treatment patients (after cryotherapy, laser, or conization): The endocervical brush collects more diagnostic material than a swab 1.
Common Pitfalls to Avoid
- Do not use the Ayre spatula alone—the extended-tip spatula is superior for sampling the transformation zone 1
- Do not use endocervical swabs except in pregnancy when concerned about other devices—they are less sensitive than the brush 1
- Do not rotate the broom back and forth—this causes cell loss 1
- Do not delay fixation of conventional smears—cellular desiccation occurs rapidly 1
- Do not use wooden spatulas with liquid-based systems—plastic releases cells more readily 1
Label all specimens with the patient's name before beginning the procedure 1.