Screening method of medullary carcinoma thyroid is:
Medullary Carcinoma Thyroid (MTC):

Neuroendocrine carcinoma arising from parafollicular ‘C’ cells of thyroid.
Parafollicular ‘C’ cells are derived from the ultimobranchial bodies and secrete calcitonin.
‘C’ Cells are concentrated superolaterally in thyroid lobes, from where MTC usually develops.
Most MTCs (75-80%) arise sporadically.
Spread is both lymphatic and hematogenous.
MC site of metastasis: Liver
Serum calcitonin
Serum calcium
Serum alkaline phosphatase
Serum acid phosphatase