Fine Needle Aspiration
Preparation of Direct Smears

For preparation of smears, single-end frosted slides should be utilized. Slides should be labeled with patient’s first and last name and specimen source in pencil prior to aspiration. Some investigators recommend to first gently express a drop of aspirated fluid onto a slide, while others recommend forcefully expelling the material onto the slide. The actual method will be determined in part by the nature of the material present. A drop may be easily expressed without force if the aspirated material is abundant and fluid. If the material is scant, or more viscous or solid, the material must often be forcefully expelled. The latter method can result in splattering of material off of the slide and will utilize most of the specimen resulting in the preparation of a minimal number of smears necessitating more passes if additional material is required for additional studies. The former method allows for better control of the smear process.

Once the specimen is on the slide, it must be smeared. The simplest way to accomplish this is to place a second glass slide onto the first (Figure 2).

a) To prepare smears, place the bevel of the needle directly on the glass slide near the frosted end. Express the aspirated material using the air-filled syringe to blow out material through the needle onto a slide in one drop. Do not spray the specimen through the air onto the slide.
b) A second or spreader slide is then used to make the smear. The spreader slide is gentle lowered, crosswise, over the droplet, which will then spread out slightly by capillary action. The spreader slide is then gently pulled straight back in one smooth motion, down the length of the diagnostic slide. Little or no diagnostic material should remain on the spreader slide.
c) Repeat the above procedure with additional drops of material to make approximately 4-6 slides. Any material that remains can be expressed into CytoRich Red™ cytology preservative (unless lymphoma is suspected and then place material in RPMI media). We prefer that air-dried smears be prepared from thyroid fine needle aspirations specimens. Do not prepare air-dried smears from other specimens sources unless discussed first with the Cytopathology Department. Follow the same procedure for preparing slides, as outlined above, when preparing air-dried smears except for the fixation step. For thyroid aspirations we recommend several unfixed slides be prepared in addition to several fixed smears. In addition, material may be submitted in CytoRich Red™ cytology preservative.

Fixation:
The smears should be:
1) Immediately fix the slides in 95% ethanol for Papanicolaou staining (delineate with an “F”, for fixed, on the frosted end of the slide).
2) Air-dried smears for Diff-Quick staining should be prepared for thyroid specimens only (delineate with an “A”, for air-dried, on the frosted end of the slide).
3) If spray fixative is used, spray 10-12 inches from slide immediately after the smear is made. Additional smears may be prepared if material remains in the hub of the needle or the material may be entirely rinsed into a specimen container containing either fixative CytoRichTM Red, CytoLyt or a physiologic solution such as normal saline (or RPMI if lymphoma is suspected). All of the aspirated material should be flushed into a physiologic solution if smears are not prepared. The advantage of submitting material in CytoRich Red™ cytology preservative is that cell block material can be prepared which facilitates utilization of special stains in evaluating the specimen. Please submit material in RPMI solution if lymphoma is suspected (arrange with the laboratory in advance by calling 202-2888 and request the clinical pathologist on call or the Tissue Laboratory at 202-1745).

Transport: Submit the specimen (smears and/or material rinsed into solution) to the Cytopathology Laboratory along with the completed test request form. The specimen should be submitted in fixative if transport of specimen in fluid will be delayed more than 24 hours.

Specimen stability: If transport time of fluid specimen will be less than 24 hours or fixative is not available then refrigerate the specimen (or keep on wet ice) until transport to the Cytopathology Department.

Reference interval: By report.

CPT code(s): 88173 This CPT code may also be reported in conjunction with aspiration of the specimen (10021) and/or immediate on-site evaluation of the specimen (88172). Additional CPT codes may be reported depending on the preparation methods, such as 88106, 88108, and/or 88305.

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