A diagnostic head and neck fine needle aspiration service can be provided using liquid-based cytology only

Liquid-based cytology (LBC) has been used for non-gynaecological specimens since its introduction into routine use in cervical cytology in the mid-1990s. There are still relatively few large studies comparing performance in reporting the head and neck fine-needle aspirations (H&N FNA) processed by LBC only to conventional direct smears (CDS).

This study compared 686 H&N FNAs processed by LBC only with 3719 CDS. All were taken under ultrasound (US) guidance by a small cohort of three consultant radiologists and reported by the author.

The (smaller) LBC sample was statistically representative of the larger CDS population at an alpha level of 0.05. There was no difference between CDS and LBC at a 95% confidence interval (CI) when comparing specificity and sensitivity (specificity: 94.8-96.5% versus 90.2-95.4%; sensitivity: 91.4-94.1% versus 86.8-93.4%). The inadequate rate between the two techniques was similar, 0.5-1.0% for CDS versus 0.7-2.5% for LBC. The significance difference was in the suspicious rate which was greater at 2.8-5.8% for LBC versus 1.7-2.6% for CDS. Consequently, there was a slight but non-significant difference between the two populations with respect to the overall accuracy: 93.5-95.1% for CDS versus 89.4-93.7% for LBC.

While there are morphological differences between LBC and CDS in H&N FNAs, once a degree of familiarity is achieved, the two techniques have equivalent sensitivity, specificity and inadequate rates.