Table 2. Diagnostic criteria for thyroid nodules and cysts.

Grade	Interpretation	Recommendation
A	Within normal
(A1)	No nodules or cystsa	Next primary examination
(A2)	Nodules ≤5.0 mmb and/or cysts ≤20.0 mm	Next primary examination
B	Nodules ≥5.1 mm and/or cysts ≥20.1 mm	Secondary examination
C	Required immediately examination	Urgent secondary examination

^aMixed cystic-solid nodule is included in the category of “nodules”.

^bNodules within the A2 category, which have ultrasonographic findings suggesting thyroid cancer with aggressive clinical features, may be classified as B.