Importance of FNA Technique for Decreasing Non-diagnostic Rates in Thyroid Nodules

To identify potential interventions that may lower the high non-diagnostic rates associated with ultrasound guided (US) fine needle aspiration (FNA) biopsy of the thyroid nodule. A case series of 164 thyroid nodule US-guided FNA was identified retrospectively. The following variables were analyzed in regards to diagnostic and non-diagnostic sampling: patient age, gender, size of nodule, biopsy technique (capillary vs. aspiration), needle gauge (23 vs. 25), and physician experience. The FNA diagnosis, and final pathology, when applicable, was recorded for each sample using the Bethesda criteria. Data was analyzed using the Fisher's exact test or the chi square test. After multivariate logistic regression, capillary action was independently associated with lower non-diagnostic rates (p = 0.01), while increasing patient age was associated with higher non-diagnostic rates (p = 0.018). Physician experience (p = 0.014) was not independently associated with lower non-diagnostic rates. Nodules that were "cystic >50%" were significantly more likely to yield a non-diagnostic result (p < 0.0001). After taking into account confounding variables, including physician experience, our data reveals a statistically significant decrease in non-diagnostic rates with the use of capillary action vs. aspiration technique in US-guided FNA. A major focus in healthcare today is providing cost-effective and minimally invasive care to the patient. In the setting of a rising incidence of thyroid disease, we believe our study demonstrates the need for a prospective analysis of the relationship between technique and non-diagnostic rates.