Investigating hypothyroidism

A 52 year old woman presents to her general practitioner with fatigue. She started to notice feeling tired more easily and getting more sleepy during the day about eight months ago and thinks it is worsening. She also notes that she has gained 10 lbs over the past year, without major changes in her diet or exercise. Her review of symptoms is positive for constipation and increased hair loss. Her medical history includes obesity, hypertension, hyperlipidaemia, and type 2 diabetes, although her hypertension and type 2 diabetes have been well controlled on her medications. Her current medications are lisinopril, atorvastatin, and metformin. Recent laboratory tests—including a full blood count, renal function panel, liver function panel, and plasma glucose—were normal. Physical examination is notable for normal vital signs, abdominal adiposity, and dry skin, but is otherwise unremarkable.

The patient notes that her mother had hypothyroidism, and she wonders if she should be tested.