Familial dysalbuminaemic hyperthyroxinemia interferes with current free thyroid hormone immunoassay methods.

CONCLUSIONS: All FT4 immunoassays evaluated are prone to interference by R218H FDH, with their varying susceptibility not being related to assay architecture but likely due to differing assay conditions or buffer composition. Added susceptibility of many FT3 assays to measurement interference, resulting in high FT4 and FT3 with non-suppressed TSH levels, raises the possibility of R218H FDH being misdiagnosed as Resistance to Thyroid Hormone beta or TSH-secreting pituitary tumour, potentially leading to unnecessary investigation and inappropriate treatment.
PMID: 32213658 [PubMed - as supplied by publisher]

Source: European Journal of Endocrinology - February 29, 2020 Category: Endocrinology Authors: Khoo S, Lyons G, McGowan A, Gurnell M, Oddy S, Visser WE, van den Berg S, Halsall D, Taylor K, Chatterjee K, Moran C Tags: Eur J Endocrinol Source Type: research