Thyroid Fine Needle Aspiration Smear Preparation

Abstract

Abstract

Introduction:

Fine needle aspiration (FNA) biopsy is used for evaluation of thyroid nodules. Overall accuracy exceeds 95% with a false negative rate between 0% and 3%.^1,2 Excellent thyroid FNA smear preparation is critical as it facilitates accurate cytologic interpretation by the pathologist.^3–5

Materials and Methods:

Standard frosted glass slides and hand lotion were used for this demonstration. In the following video we present two techniques: a three-slide technique and a two-slide technique.

1. The “classic” technique uses three slides and generates two slides for interpretation. A slide to be deposited in fixative (a), a slide to be air dried (b), and a spreader slide (c), which is typically discarded.

Technique:

• • Place a small drop of material on the top one-third and the center of the slide (a).

• • Pick up the slide (a) from the edges and using your nondominant hand pinch the frosted end between your thumb and index finger and use the remaining fingertips of this hand to support the back of the slide.

• • Pick up the spreader slide (c) with your dominant hand and bring it across slide (a).

• • Use the top edge of the spreader slide closest to your hand to pick up a small amount of material, lift up, and advance the slide laterally.

• • Using a clean area of the spreader slide, press down gently on the remaining material on slide (a) and pull the spreader slide (c) towards yourself to smear the material.

• • Drop the first smear slide (a) into fixative immediately.

• • Pick up the second slide (b) and using the spreader slide (c) apply gentle pressure downward with the first sample pick up and pull toward yourself to spread the material.

• • Rest slide (b) and allow for complete air drying of the material.

2. The two-slide technique has been called the “butterfly” or “book-end” technique. It has the advantage of simplicity and better reproducibility. It produces a relatively uniform and rounded imprint of FNA material for evaluation on two mirror image slides.

Technique:

• • Place a small drop on the top one-third and center of the first slide.

• • Pick up the two slides by holding the frosted end pinched between your thumb and index finger.

• • Hold the second slide in a perpendicular orientation over the bottom slide containing the droplet. You should appreciate a “+” or “x” with the two slides.

• • Gently press down on the first slide until the slides feel stuck together.

• • Quickly separate the two slides in one motion by pulling the second slide straight up. The result will be a mirror image of the specimen on each slide.

• • Quickly drop one of the slides into fixative and allow the other to completely air dry.

Conclusions:

Proper thyroid FNA smear technique is essential for ensuring slides of high technical quality for cytologic interpretation.

No competing financial interests exist.

Runtime of video: 6 mins 41 secs