Patients with TSH-Receptor Blocking Antibodies Give a “Positive” Result for Stimulating Activity in Several Commercial Assays

SpauldingStephen, W

doi:10.1089/ct.2016;28.206-207

Cited by 2 publications

(1 citation statement)

References 2 publications

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“…Also, the presence of blocking TSHR Ab had a significant impact on the probability of remission. Finally, blocking TSHR Ab caused hypothyroidism in patients with AITD, foremost in HT [25,26].…”

Section: Discussionmentioning

confidence: 99%

Performance and Specificity of 6 Immunoassays for TSH Receptor Antibodies: A Multicenter Study

Diana¹,

Wüster²,

Olivo³

et al. 2017

Eur Thyroid J

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Background: The measurement of TSH receptor (TSHR) antibodies is warranted for diagnosis of Graves' disease (GD).Objective: The performance, detection sensitivity, and specificity of 6 TSHR immunoassays were compared. Methods: Two bioassays and 4 binding assays (Kronus, Immulite, Kryptor, Dynex) were compared in a dilution study performed in patients with autoimmune thyroid disease. Both bioassays were compared to 2 binding assays using stimulatory (M22) and blocking (K1-70) monoclonal antibody (MAb) mixtures. Results: Thirty samples from stimulatory (TSAb)-positive/blocking (TBAb)-negative patients with GD were diluted serially and measured in all assays. Samples were positive until dilution 1:2,187 in the TSAb bioassay, 1:81 in the Immulite (p < 0.002 vs. bioassay) and Kronus ELISA (p = 0.039) assays, and 1:27 in the Kryptor and Dynex ELISA (p < 0.001 vs. bioassay). Ten samples from TBAb-positive/TSAb-negative patients with GD or Hashimoto's thyroiditis were positive in all binding assays. None of the binding assays differentiated between TSAb and TBAb. Mixtures of 100% K1-70 (200 ng/ mL), 80% K1-70 + 20% M22, 60% K1-70 + 40% M22, 40% K1-70 + 60% M22, 20% K1-70 + 80% M22, and 100% M22 (20 ng/mL) tested positive in both Immulite (26.4, 20.2, 15.2, 10.5,6.3, 2.00 IU/L) and Kronus assays (27.1, 23.3, 19.3, 12.0, 5.7, 2.2 IU/L). These MAb mixtures were tested in the TBAb bioassay and showed 82, 61, 24 (negative), -26 (negative), -77 (negative), and -95% (negative) inhibition, respectively. Conclusions: The sample dilution study showed higher detection sensitivity for the TSAb bioassay, and the antibody mixture study demonstrated exclusive specificity of the bioassays over all automated and ELISA binding assays.

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Section: Discussionmentioning

confidence: 99%