Fine Needle Aspiration and smear making

Summary

This video demonstrates how to perform a fine needle aspirate (FNA) on a dog to collect cells for cytologic evaluation. The procedure involves using a small gauge needle to aspirate material from a lump or mass, which is then smeared onto slides for microscopic analysis. The process is quick and minimally invasive, causing little discomfort to the animal. After the aspirate, slides are prepared, air-dried, labeled, and submitted to a diagnostic lab for further examination. The video also emphasizes the importance of ensuring high-quality samples for accurate diagnosis and proper labeling for proper identification.

Takeaways

• 😀 FNAs (Fine Needle Aspirates) are a minimally invasive procedure to collect cells for cytologic evaluation.
• 😀 This procedure is typically well-tolerated by animals, with minimal discomfort, similar to vaccinations.
• 😀 A 22-gauge needle is recommended for the procedure to avoid blood contamination of the sample.
• 😀 A syringe, typically ranging from 3ml to 12ml, is used to collect the aspirate.
• 😀 The procedure involves inserting the needle into the mass, applying negative pressure, and redirecting the needle within the mass 2-4 times.
• 😀 After aspirating, the syringe is detached from the needle, and the material is expressed onto slides for cytology smears.
• 😀 The slide-over-slide technique is used to make cytology smears, where a second slide is used to spread the material from the first slide.
• 😀 The smears should be air-dried quickly before labeling with patient information, such as the animal's name, the owner's name, and the site of the sample.
• 😀 Multiple smears are recommended, typically two to three per site, and additional aspirates may be performed if necessary.
• 😀 Smears should be submitted to a diagnostic laboratory in a slide protector, ensuring that formalin-fixed specimens are kept separate.
• 😀 It is a good practice to stain one of the smears in the clinic to confirm the adequacy of the sample before submitting it to a lab.

Q & A

What is a fine needle aspirate (FNA)?

A fine needle aspirate (FNA) is a procedure where a needle is inserted into a mass to obtain cells for cytologic evaluation under a microscope. It helps in diagnosing the nature of the lump or mass.

What is the purpose of performing an FNA on a dog with a lump?

The purpose is to obtain cells from the lump to perform a cytologic evaluation, which helps in diagnosing the nature of the lump, whether it's benign or malignant.

Why is a 22 gauge needle typically used for FNA?

A 22 gauge needle is commonly used because it is small enough to avoid excessive blood contamination in the sample. Using a needle larger than 22 gauge can cause blood contamination, which affects the quality of the sample.

How is the needle inserted during the FNA procedure?

The needle is inserted into the mass while immobilizing it with the left hand. The needle is then redirected within the mass, usually two to four times, while negative pressure is applied to draw cells.

What is the slide-over-slide technique for preparing cytology smears?

The slide-over-slide technique involves placing a drop of material onto a slide, then using another slide at a right angle to spread the material across the slide to make a thin, even smear.

Why is it important to air dry the smears after creating them?

Air drying the smears is important because it helps preserve the cells on the slide for examination. The material dries quickly and is ready for labeling and submission once dry.

What information should be included when labeling a cytology smear?

The label should include the animal's name, the owner's name, and the site of the mass where the sample was taken.

How many smears should be made from each site during an FNA procedure?

Ideally, two to three smears should be made from each site. In some cases, more smears may be required if the initial sample is insufficient.

Why should FNA smears not be submitted with formalin-fixed specimens?

Formalin-fixed specimens cause cell disintegration, which would ruin the cytology sample. FNA smears should be submitted separately to maintain the integrity of the cells.

What should be done with one of the smears after the FNA procedure?

It is a good practice to stain one of the smears at the clinic using a quick stain, like Protocol Hema 3, to ensure the sample quality before submission to a diagnostic lab.