Congenital hypothyroidism (CH) is an endocrine disorder of newborns characterized by decreased levels of thyroid hormones: thyroxine (T4) and triiodothyronine (T3) in peripheral blood. In early peri­natal period manifestations of CH are often non-specific, subtle or even non-existent [1-2]. Howev­er, the disease, if undiagnosed and untreated, leads to severe mental retardation, as well as to growth and developmental disturbances. Due to the high incidence of CH worldwide (on average one in 4000 live births) and to the availability of inexpensive and effective replacement therapy by L-thyroxine, this disorder is screened for in all industrialized and a majority of developing countries [3]. Newborn screening for CH has proved to be highly cost effective