Endocrine Abstracts

Positive interference in free thyroxine (fT4) and free triiodothyronine (fT3) immunoassays is well known, however we report a rare case of negative interference in the Roche fT4 and fT3 immunoassays in a 3-year-old girl with undetectable fT4 and fT3. She presented with increasing tiredness, abdominal pain, pain in her lower limbs and constipation. Examination was unremarkable. Thyroid func...