Conduite à tenir face à un bilan thyroïdien anormal

Thyroid function tests are often used to diagnose thyroid diseases. Difficulty in interpretation of biochemical results or discrepancies between circulating concentration of thyroid hormones or TSH and the clinical status often occur. In fact, in moderate degrees of hypo and hyperthyroidism, concentration of thyroid hormones may remain within the reference range. In addition, many drugs and non thyroidal diseases through alterations in the synthesis, transport and metabolism of thyroid hormones may cause changes in the serum concentration of these hormones or exert direct effect on the secretion of thyrotrophin (TSH). Last, interferences in thyroid assays may result in abnormal values in thyroid functional assessments. All these factors may lead to false diagnosis of thyroid disease in euthyroid patients and it may be necessary to perform additional investigations before concluding when a potential abnormality is recognized.