Test Details: Immunohistochemical testing is carried out on biopsy/resected tissue specimen. This testing helps to identify specific antigens (proteins) within tissue sections utilizing an antigen-specific antibody. Calcitonin (thyrocalcitonin) is a 32 amino acid linear polypeptide hormone (molecular weight 3,421Kd) that participates in calcium and phosphorus metabolism. It is used as a marker for medullary thyroid carcinoma (MTC).