Elevated serum calcium level (Sipple's syndrome)
Elevated serum calcitonin level (Medullary carcinoma)
Elevated serum CEA level
Thyroid hormone assays
Ultrasound
Scintigraphy after radioisotope administration (low uptake)
Radioiodine scan (cold lesion)
Fine needle aspiration cytology
Aspiration biopsy
Chest X ray for detection of pulmonary metastases
C.T. scan of neck
Bone scan for detection of bony metastases