False-positive TSH receptor antibody-a pitfall of third-generation TSH receptor antibody measurements in neonates.

False-positive TSH receptor antibody-a pitfall of third-generation TSH receptor antibody measurements in neonates. Endocr J. 2018 Mar 10;: Authors: Wada M, Kita M, Kawasaki K, Kusakabe T, Tagami T, Satoh-Asahara N, Shimatsu A, Hashimoto K Abstract Maternal Graves' disease (GD) during pregnancy may influence thyroid function in fetuses. Neonates born to mothers with high serum TSH receptor antibody (TRAb) levels have been reported to develop 'neonatal GD'. Therefore, evaluations of serum thyroid hormone and TRAb levels in neonates upon birth are crucial for a prompt diagnosis. At delivery, we measured TRAb with third-generation TRAb test using an M22 human monoclonal antibody in neonates by collecting umbilical cord blood in a blood collection tube with lithium-heparin, which provides a whole blood/plasma sample. In recent years, we have encountered positive TRAb levels (more than 2.0 IU/L) in nineteen neonates born to mothers with GD whose thyroid hormone levels were almost within the reference range and serum TRAb levels were less than 10 IU/L. All the neonates with positive TRAb levels did not exhibit thyrotoxicosis. However, when we measured TRAb levels with serum sample in six out of the nineteen cases, their serum TRAb levels were all negative, suggesting a discrepancy of TRAb levels between in lithium-heparin plasma from umbilical cord blood and serum. Moreover, this discrepancy was observed in neonates born to euthyroid mother...
Source: Endocrine Journal - Category: Endocrinology Tags: Endocr J Source Type: research