A 55-year-old woman presents to your office with complaints of fatigue, dry skin, constipation and weight gain. Physical exam results include a heart rate of 58 bpm and diminished deep tendon reflexes. Laboratory testing reveals an elevated TSH. Which of the following is the most appropriate next step in management?
Begin treating patient with a beta-blocker
Begin treating patient with levothyroxine
Test serum free T3
Test serum free T4
