Circulating Antibodies to T4 Causing Discordant Tests of Thyroid Function: A Case Report

Misleading free t4 due to auto-t4 antibodies resulting in abnormal thyroid function tests: a case report

“…Non-specific binding of heterophile antibodies, thyroid autoantibodies or rheumatoid factor may interfere with thyroid hormone measurement. The prevalence of anti T4 and T3 antibodies in the general population is estimated to be 10% and in autoimmune thyroid disease about 40% (9). This patient had very high titres of anti-TPO antibodies.…”

“…This patient had very high titres of anti-TPO antibodies. Autoantibodies to thyroid hormones may lead to abnormal FT4 by interference with the one step tests (9,10). This also causes artefacts in total T4 measurement.…”