Exclusion criteria rendering TNAPP unsuitable for the evaluation of thyroid nodules include a prior history of thyroid cancer or hereditary/familial differentiated thyroid cancer in those with predisposing genetic syndromes (Gardner, Cowden, Adenomatous Familial Polyposis, Werner, Carney’s complex), positron emission tomography positive nodules, elevated calcitonin, and suspicious or malignant regional adenopathy. The gene discussed is CALCA; the disease is thyroid cancer.