New reference intervals for thyrotropin and thyroid hormones based on National Academy of Clinical Biochemistry criteria and regular ultrasonography of the thyroid.

Background: The aim of our present study was to establish new reference intervals for thyrotropin (TSH) and thyroid hormones based on National Academy of Clinical Biochemistry (NACB) criteria and regular thyroid ultrasonography. We also assessed the effect of potentially confounding factors to modulate the limits of these intervals.

Methods: We investigated 870 apparently healthy persons and excluded, step by step, those with a family history of thyroid disease, pathologic thyroid ultrasonography results, and increased anti-thyroid peroxidase or anti-thyroglobulin antibodies.

Thyroglobulin mRNA quantification in the peripheral blood is not a reliable marker for the follow-up of patients with differentiated thyroid cancer.

Background: The detection of serum thyroglobulin (Tg) by immunoassay is widely used to detect residual, recurring or metastatic thyroid carcinoma tIssue in patients with differentiated thyroid cancer (DTC) after total thyroidectomy and radioiodine therapy. However, this method requires thyroid hormone withdrawal to increase sensitivity and is limited by the interference of anti-Tg antibodies. To solve these problems, the detection of Tg mRNA from circulating thyroid cells by reverse transcription (RT)-PCR has been suggested as an alternative method.