Non-diagnostic rates for thyroid fine needle aspiration are negatively correlated with positive for malignancy rates.

INTRODUCTION

Non-diagnostic rates for thyroid fine needle aspiration vary considerably, but reasons for this variation are poorly understood.

METHODS

Our group reviewed the results of all thyroid aspirations with surgical resection for the last 13 years at our institutions, combined these with those in the literature, and correlated non-diagnostic rates with positivity rates.

RESULTS

Non-diagnostic rates were negatively correlated with positivity rates (R2=0.55). Studies that had significantly lower non-diagnostic rates than the rest of the literature (2 vs. 15%, p=0.002) had different or undefined adequacy criteria or used core biopsies in addition to fine needle aspiration.

CONCLUSIONS

Non-diagnostic rates for thyroid fine needle aspirations are negatively correlated with positivity rates. These data provide more realistic estimates of achievable adequacy rates.