The Netherlands journal of medicine
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Autoantibodies against the thyroid stimulating hormone receptor, thyrotropin receptor autoantibodies (TRAb) are diagnostic for Graves' disease and can be measured by different methods. As antibody concentrations are not comparable between methods, appropriate cut-off values need to be established for every single method. For a third-generation TRAb assay (Phadia, Thermofisher), the manufacturer determined the cut-off value in a study population consisting of Graves' disease (both newly diagnosed and patients under treatment) and non-Graves' disease patients. The aim of this study was to verify whether this cut-off value holds true in our population. ⋯ The cut-off value of this immunoassay should probably be set higher in untreated Graves' patients than proposed by the manufacturer as the cut-off value should be determined in a study population excluding Graves' patients under treatment. The overall clinical picture remains crucial in the diagnosis of Graves' disease.