Reducing the Number of Unnecessary Thyroid Biopsies While Improving Diagnostic Accuracy: Toward the "Right" TIRADS

J Clin Endocrinol Metab. 2019 Jan 1;104(1):95-102. doi: 10.1210/jc.2018-01674.


Context: The prevalence of thyroid nodules in the general population is increasingly high, and at least half of those biopsied prove to be benign. Sonographic risk-stratification systems are being proposed as "rule-out" tests that can identify nodules that do not require fine-needle aspiration (FNA) cytology.

Objective: To comparatively assess the performances of five internationally endorsed sonographic classification systems [those of the American Thyroid Association, the American Association of Clinical Endocrinologists, the American College of Radiology (ACR), the European Thyroid Association, and the Korean Society of Thyroid Radiology] in identifying nodules whose FNAs can be safely deferred and to estimate their negative predictive values (NPVs).

Design: Prospective study of thyroid nodules referred for FNA.

Setting: Single academic referral center.

Patients: Four hundred seventy-seven patients (358 females, 75.2%); mean (SD) age, 55.9 (13.9) years.

Main outcome measures: Number of biopsies classified as unnecessary, false-negative rate (FNR), sensitivity, specificity, predictive values, and diagnostic ORs for each system.

Results: Application of the systems' FNA criteria would have reduced the number of biopsies performed by 17.1% to 53.4%. The ACR Thyroid Imaging Reporting and Data System (TIRADS) allowed the largest reduction (268 of 502) with the lowest FNR (NPV, 97.8%; 95% CI, 95.2% to 99.2%). Except for the Korean Society of Thyroid Radiology TIRADS, all other systems exhibited significant discriminatory performance but produced significantly smaller reductions in the number of procedures.

Conclusions: Internationally endorsed sonographic risk stratification systems vary widely in their ability to reduce the number of unnecessary thyroid nodule FNAs. The ACR TIRADS outperformed the others, classifying more than half the biopsies as unnecessary with a FNR of 2.2%.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biopsy, Fine-Needle / statistics & numerical data*
  • False Negative Reactions
  • Female
  • Humans
  • Male
  • Middle Aged
  • Predictive Value of Tests
  • Prospective Studies
  • Risk Assessment
  • Sensitivity and Specificity
  • Thyroid Gland / pathology*
  • Thyroid Nodule / diagnostic imaging*
  • Thyroid Nodule / pathology*
  • Ultrasonography
  • Unnecessary Procedures