Useful tools in differentiating these two types include thyroid autoimmunity evaluation (positive in type I), thyroid ultrasonography (usually abnormal in type I), thyroid color flow Doppler sonography (homogeneous pattern with increased vascularity in type I and heterogeneous pattern with low vascularity in type II) and serum IL-6 levels (usually increased in type II) [3]. Here, IL6 is linked to autoimmune thyroid disease.