RF35 | PSAT304 A Case of COVID-19 Infection; COVID-19 mRNA-Based Vaccine Induced Human Anti-Mouse Antibodies (HAMA) Interfering With TSH Testing

: A 71-year-old male presented to the endocrine clinic for evaluation of hypothyroidism which has recently been difficult for his primary care physician to control. He initially developed hypothyroidism in 1990 after neck radiation for squamous cell carcinoma of his sternocleidomastoid muscle. He was previously controlled for many years on levothyroxine 150mcg daily with TSH readings in the normal reference range. Patient was infected with COVID-19 in 2020 and was hospitalized for 10 days. He was treated with 5 days of Remdesivir and 10 days of Decadron. 6 months after the infection he received mRNA COVID-19 vaccination. Upon his first visit to the endocrine clinic post COVID-19 infection and vaccination, his TSH was elevated at 90 uIU/mL with a free thyroxine that was elevated at 1.8 ng/dL even after multiple attempts by his primary care physician to increase his Levothyroxine which was up to 225 mcg daily before he was referred to endocrinology. He is compliant with his levothyroxine and takes it on an empty stomach first thing in the morning without any of his other medications. He is not taking iron supplements, biotin or any other supplements or new medications. TSH values had been normal 1 month prior to his COVID-19 infection and was first noted to be abnormal 8 months after his COVID-19 infection and 2 months after his mRNA COVID-19 vaccine. There was no TSH drawn between when he had COVID-19 and when he received his vaccine. It was suspected that he may have a factitious elevation in his TSH due to antibody interference. Labs were drawn for a TSH with human anti-mouse antibodies (HAMA) treatment which resulted with a markedly suppressed TSH at 0.007 uIU/mL with an elevated free thyroxine of 1.94 ng/dL. HAMA antibodies came back elevated at 552 ng/mL. REFERENCE: Klee, G., 2000. Human Anti-Mouse Antibodies. Archives of Pathology & Laboratory Medicine, 124(6), pp.921-923. Koshida, S., Asanuma, K., Kuribayashi, K., Goto, M., Tsuji, N., Kobayashi, D., Tanaka, M. and Watanabe, N., 2010. Prevalence of human anti-mouse antibodies (HAMAs) in routine examinations. Clinica Chimica Acta, 411(5-6), pp.391-394. Presentation: Saturday, June 11, 2022 1:00 p.m. - 3:00 p.m., Monday, June 13, 2022 1:00 p.m. - 1:05 p.m.