title: [FT4 immunoassay interference : A case report].
abstract: Measurement of thyrotropin and free thyroxin made using immunoassays are usually needed in clinical endocrinology. Here, we report a case of a patient with type 2 diabetes who presented a weight loss. To eliminate hyperthyroidism, thyroid function tests were performed. Free thyroxin (FT4) was decreased using two automated immunoassays TOSOH AIA 1800 and Roche ELECSYS 2010, with a normal thyrotropin value. Thyroid function tests repeated a month later were normal. The patient's history revealed contact with sheep, which may partly explain the interference. Investigations into the patient's serum were carried out using both the PEG test and dilution test. Interference factors were probably antibodies. Despite progress in immunoassays, we should be aware of interference occurrence since it can lead to false results, unnecessary investigations and incorrect treatment. Thus, simple tests must be carried out as if interference in immunoassays were suspected. Dilutions and PEG tests are generally performed as first line investigations.
authors.forename: Khansa
authors.initials: K
authors.lastname: Chaabouni
authors.forename: Khaoula
authors.initials: K
authors.lastname: Hargafi
authors.forename: Aida
authors.initials: A
authors.lastname: Elleuch
authors.forename: Mariem
authors.initials: M
authors.lastname: Messedi
authors.forename: Mouna
authors.initials: M
authors.lastname: Turki
authors.forename: Amina
authors.initials: A
authors.lastname: Lahyani
authors.forename: Fatma
authors.initials: F
authors.lastname: Ayedi
mesh_terms: D000368:Aged; D000818:Animals; D003924:Diabetes Mellitus, Type 2 / Q000503:physiopathology; D006801:Humans; D006980:Hyperthyroidism / Q000175:diagnosis*; D007118:Immunoassay / Q000379:methods; D008297:Male; D012756:Sheep; D013960:Thyroid Function Tests / Q000379:methods; D013972:Thyrotropin / Q000032:analysis*; D013974:Thyroxine / Q000032:analysis*; D015431:Weight Loss
chemical_list: D013972:Thyrotropin; D013974:Thyroxine