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Microbiology - Specimen Collection Device Change - Effective March 2024

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Fine Needle Aspiration

For fine needle aspiration specimens, the following specimen collection and sample preparation guidelines are recommended.

Proper aspiration technique and subsequent sample submission with appropriate and immediate fixation are crucial for optimal case assessment and outcome.

Equipment / materials

  • 22-25 gauge needles with transparent hubs
  • 10 mL syringes (preferably a "pistol grip" syringe holder or other device which frees the other hand to palpate/secure the lesion to be aspirated)
  • Glass Slides
  • Fixative Solution

Procedure

  • Label the frosted end of slides with the patient's full name (first and last), date of birth and sample collection site.
  • Attach a needle to the syringe with plunger almost fully depressed.
  • After proper cleansing of skin (and if necessary, local anesthesia of area to be aspirated) immobilize mass with one hand.
  • Without suction, pass the needle directly into the mass.
  • Exert suction and move needle within mass with short vibrating movements (5 to 10 or until fluid appears in the hub of the needle, whichever occurs first).
  • Gently but promptly release suction before removing needle from the mass. If suction is continued while removing the needle from the mass and overlying skin, the sample may be largely drawn into the barrel of the syringe where it is difficult to retrieve. Air drying may also occur.
  • Withdraw the needle from the patient, again making certain no air is aspirated.
  • With the bevel of the needle pointing down and close to the surface of the slide, express a drop (not greater than 4-5 mm in diameter) of specimen onto a slide.
  • Place a second glass slide flat and face down on top of the specimen drop allowing the fluid to spread evenly by capillary action. When maximally spread, separate the slides along the long axis of the slide and apply fixative immediately.
  • After making the smears, rinse the needle in Cytolyt® Preservative solution by aspirating and ejecting the Cytolyt® solution 2-3 times.
  • If obvious cyst fluid is obtained, the entire specimen may be submitted in Cytolyt® (up to 30 cc per vial).
  • Several aspirates are often necessary for adequate sampling. A 25 gauge needle is generally best for aspirates from highly vascular lesions.