Smears of the anal canal are most often collected in patients with suspected HPV infections of the anal canal, and patients with HIV infection to identify specific infections (such as HPV and herpesvirus) or malignancy.
Method of Collection
There are two methods for collecting cytologic specimens from the anal canal: the conventional smear technique and collection of the specimen in a liquid fixative (Thin Prep method). In each instance, a tap water-moistened Dacron swab is inserted into the anal canal for a distance of 5-6 cm. Firm lateral pressure should be applied to the swab handle as it is rotated and slowly withdrawn from the anal canal. Note: Cotton swabs on a wooden stick should be avoided because the wooden handle may break and splinter during collection. Collection in a liquid fixative is preferred because it avoids the artifacts of air drying and mechanical distortion that are common in smeared preparations.
The Conventional Smear
- Smear the material on a glass slide without applying too much pressure.
- Fix the smear in alcohol promptly, either by spraying with an alcohol spray, or by covering the slide with alcohol from an alcohol pouch.
- Label the slide with the patient’s name.
- Place the slide in a secure plastic or cardboard slide holder to avoid breakage.
- Make a note on the requisition form that the smear has been fixed in alcohol so that the smear can be stained appropriately (smears fixed in alcohol are stained differently from air-dried smears).
- Complete the Calpath requisition form per the instructions.
Thin Prep Method
- Obtain an adequate sample from the anal canal using a water- moistened Dacron swab as described above.
- Immediately immerse the swab in the PreservCyt Solution and vigorously agitate the swab in the liquid to release the cellular material.
- Remove the swab and close the container securely.
- Write the patient’s name and physician’s name on the specimen container.
- Complete the Calpath cytology requisition form per the instructions.
- Place the specimen in the Calpath specimen bag.
- Place the requisition form in the side slot of the Calpath specimen bag.
- Call Calpath for a pickup or
- Place the Calpath specimen bag in the location where our courier usually picks up your daily specimens.