Functioning nodules rarely harbour malignancy.[12] Calcitonin may be a useful serum marker of medullary thyroid carcinoma.[13] A baseline serum calcitonin value of 10 to 100 pg/ml is abnormal (normal baseline <10 pg/ml) and should result in further investigation; values that exceed 100 pg/ml are highly suggestive of medullary thyroid carcinoma.[14] In the initial diagnosis of thyroid malignancy, computerized tomography (CT) scanning and magnetic resonance imaging (MRI) can not provide higher quality images of the thyroid and cervical nodes than ultrasonography (US). This evidence concerns the gene CALCA and medullary thyroid gland carcinoma.