Fine-needle aspiration: technique and smear preparation.

Fine-needle aspiration is a rapid, accurate and inexpensive method to obtain a tissue specimen for diagnosis of suspicious lesions. The number of fine-needle aspirations performed can be expected to increase in this era of cost-conscious medicine. However, an accurate diagnosis is highly dependent on the quality of the smears, adequate clinical information and the experience of the pathologist. The clinician must be able to perform this procedure skillfully and provide good smears. Fine-needle aspiration skills can be learned by using the techniques described in this article and by continued training and experience. The most important factors are immobilization of the mass, the use of very small fine needles, sampling both with and without aspiration, use of multiple passes with the needle, reaspiration of any residual mass after fluid drainage if a cyst is encountered, aspiration of the margins of large masses, the two-slide smearing technique and rapid fixation of smears. Finally, extensive clinical information must be supplied to the pathologist interpreting the smears.