Question category: Rheumatology
A 50 year old female presents with weight gain. On further questioning she complains of cold intolerance, tiredness, arthralgia and she has noticed her hair and nails becoming more brittle and her mood has been low. On examination she is bradycardic and mildly oedematous. Bloods reveal a normochromic normocytic anaemia. What test should be performed to confirm the diagnosis?