Falsely diagnosed thyrotoxicosis caused by anti-streptavidin antibodies and pre-wash procedures

• Main Authors: Takuya Ishikawa, Hiroyuki Sakai, Tokutaro Itaya, Suwanai Hirotsugu, Jumpei Shikuma, Takashi Miwa, Ryo Suzuki, Masato Odawara
• Format: Article
• Language: English
• Published: BMC 2021-07-01
• Series: Thyroid Research
• Subjects: Immunoassay interference; Thyroid function tests; Anti-streptavidin antibody; Pre-wash
• Online Access: https://doi.org/10.1186/s13044-021-00108-y

Abstract Background Anti-streptavidin antibodies are causal determinants of analytical interference during Thyroid function tests, and numerous reports have detailed such interference, with anti-streptavidin antibodies attracting attention. Case presentation We conducted a straightforward investigation of interference due to anti-streptavidin antibodies, with a case of a 60-year-old Japanese man who consulted our department for inconsistencies between his clinical course and Thyroid function tests. Experiments were conducted using Cobas8000 e602, which employs assay procedures with pre-wash to evaluate FT4 and FT3 levels. Conclusions To our knowledge, this is the first published report to clearly investigate such interferences using a combination of polyethylene glycol precipitation, heterophilic blocking tube precipitation, streptavidin-coated magnetic particle precipitation, and different instruments with or without pre-wash. Clinicians should consider that interferences caused by anti-streptavidin antibodies could lead to a misdiagnosis of thyrotoxicosis. Moreover, discussions between laboratory specialists, clinicians, and manufacturers are required to identify interferences and avoid unnecessary examinations and inappropriate treatment.