Elevated calcitonin and procalcitonin levels in nonmedullary benign and malignant thyroid nodules.

Background. To evaluate the elevation rate of serum markers calcitonin (CT) and procalcitonin (ProCT) in patients with non-medullary benign and malignant thyroid nodules. Methods. Before surgery CT and ProCT were measured in sera from 168 patients with histologically proven benign thyroid nodules (n=107) and non-medullary thyroid carcinomas (n=61). Sera from 112 apparently healthy blood donors were used as controls. Results. Elevations in CT and ProCT levels were observed in 5 (2.9%) and 1 (0.5%) of 168 patients (p<0.01) with benign nodules, but non-medullary thyroid carcinomas. Conclusions. Serum proCT showed a significantly lower false-positive rate than CT in patients with non-medullary benign and malignant nodules of the thyroid gland. Key-words: medullary thyroid carcinoma, calcitonin, procalcitonin