Endocrine Abstracts

Mrs X (aged 79) had a history of longstanding hypothyroidism (levothyroxine 100 micrograms daily). Her Free T4 (FT4) had been slightly raised with normal TSH until in Dec 2019, where both became elevated (TSH 5.4 mU/l and FT4 29.4 pmol/l). Repeat TFT in January 2020 also showed the same. Mrs X felt well on Levothyroxine, with no thyrotoxic features. Endocrine clinic investigations (October 2020) showed no evidence of assay interference. Alternative diagnoses such as thyrotropi...