CALCA and thyroid nodule: In the study based on an analysis of calcitonin level in 72,368 patients with thyroid nodules, Verbeek et al. demonstrated that for the calcitonin threshold value of 10 pg/mL, the sensitivity of the test is 100% (95% CI: 99.7–100); and the specificity is 97.2% (95% CI: 95.9–98.6) [30].