[T3- and T4-antibodies in serum: screening and specific determination methods]

Endogenous antibodies against T3 or T4 may falsify the radioimmunological determination of T3 and T4. Depending on the method of separation increased or decreased values will result. The clinical aspects are at variance with these radioimmunologically measured values. The TSH value is frequently elevated and the TRH test mostly positive. The determination of unspecific binding capacity allows the selection of suspect sera. In cases of increased binding capacity the diagnosis will be established by a precipitation reaction with human-anti-Ig-G and quantified with radio-T3 or radio-T4.