Table 1. Comparison of ATA and local best practice recommendations.

ATA = American Thyroid Association; LBP = local best practice; FNA = fine-needle aspiration

Adapted from the Princess Margaret Cancer Centre Clinical Practice Guidelines [10,21]

Sonographic Pattern	Risk of Malignancy	ATA Recommendations	LBP Recommendations
Benign	< 1%	No biopsy	FNA at > 4 cm
Very Low Risk	< 3%	Consider at > 2 cm	FNA at > 4 cm
Low Risk	5 - 10%	FNA at > 1.5 cm	FNA at > 2 cm
Intermediate	10 - 20%	FNA at > 1 cm	FNA at > 2 cm
High Risk	70 - 90%	FNA at > 1 cm	FNA at > 1 cm