P NORMAL TFT , THD AB POSITIVE WHAT TO DO

• Thyroid antibodies: thyroid peroxidase (TPO) and thyroglobulin (TG). These tests are of value when a child is found to have an elevated TSH level, as a very high level of antibodies strongly suggests a diagnosis of autoimmune thyroiditis. However, this test is positive in a relatively high proportion of the general population (10% to 11% in a recent national survey, with prevalence increased in females and with increasing age).2 It follows that a large number of people who have these antibodies are not hypothyroid and will never become hypothyroid. If the free T4 and TSH are normal, is it helpful to know that a child has positive antibodies? Although a few endocrinologists treat such patients on the theory that they have mild hypothyroidism despite the normal TSH, there are no controlled studies showing benefit and few pediatric endocrinologists would treat. Relative to the normal population, such children have a greater chance of becoming hypothyroid in the future, but that could be years down the road. In my view, annual thyroid testing for a healthy child with thyroid antibodies but no goiter and a normal T4 and TSH is not worthwhile. Others may disagree.