Endocrine Abstracts

Background/objectives: While patients are commonly referred to endocrinology with a low FT4 and normal TSH, there is no consistency in the management of these patients. The aim of this audit was to assess management of these patients including investigation, diagnosis and pharmacological intervention and compare to the current Association for Clinical Biochemistry guidelines.

Methods: This was a retrospective audit studying 41 endocrine outpatients at University Hospital of Wales with TFTs at referral showing low T4 and normal TSH. Clinical history was analysed to look for mutual patient factors which may have contributed to anomalous results. The main diagnosis of interest was of pituitary macroadenomas.

Results: Good clinical history, repeat TFTs and anterior pituitary tests were obtained for all patients. 53.7% of patient had concurrent neuropsychological conditions. 19/41 patients were on antidepressants and 11/41 on anticonvulsants. No assay interference was identified in 7/7 samples analysed. 17/41 (41.5%) of patients had normalisation of their TFTs on repeat testing: patients with normal pituitary anterior pituitary hormone tests were more likely to have TFT normalisation (55.6%) in comparison to patients with abnormal pituitary results (30.4%). 3/41 patients were found to have macroadenomas but all these had other abnormal pituitary tests. No significant difference was found in baseline FT4 of patients with macroadenomas to those without.

Conclusion/ interpretation: Neuro-psychiatric conditions and/or their drugs were common in this cohort. Patients found to have a macroadenoma had abnormalities in other anterior hormone tests; 41.5% of patients referred had normalisation of their TFTs. The majority of patients had an unknown cause of anomalous TFTs not requiring intervention. A pathway may aid appropriate referral to endocrinology.