Hence, the calcitonin test almost completely prevents the risk of missing a diagnosis of medullary thyroid carcinoma, wherein the positive predictive value for the increased calcitonin level is as low as 7.7%; i.e., more than 90% of patients with an increased calcitonin level did not actually have MTC, and the surgery was either too radical or was not needed at all. The gene discussed is CALCA; the disease is medullary thyroid gland carcinoma.