Regional reference values of thyroid gland volume in Turkish Adults.

INTRODUCTION It is important to know the size of the thyroid gland, and its normal value may vary among different geographic regions. OBJECTIVE In this study, we aimed to establish reference ranges for thyroid volume in euthyroid adults and to compare these results with the literature data. METHODS Between June 2011 and June 2012,461 patients with normal laboratory results (serum TSH, anti-TG, anti-TPO antibodies and urine iodine level) that underwent thyroid gland ultrasound examination were retrospectively analyzed.Two hundred and 92 patients were females and 169 were males; the age range was 18-61 years with mean age 30.84±9.97 years. Length, breadth and thickness were measured, and the volume of each lobe was estimated using the ellipsoid formula. RESULTS The overall mean thyroid volume in all patients who were examined was 12.98±2.53 mL. The mean thyroid volume in females and males was 12.09±2.05 mL and 14.53±2.55, respectively (p<0.05). The right thyroid lobe volume was greater than the left in all patients of both sexes. In addition, the study establishes a significant correlation between the thyroid volume and height, weight and body surface area of the subjects of both sexes (p<0.05). In the light of our findings we can provide reference values in order to evaluate patients who have thyroid hyperplasia or who are considered as normal. CONCLUSION We consider that further studies are necessary to establish national references thyroid volume for each country.