A 26-year-old woman is evaluated for a 6 week history ofnervousness, heat intolerance, and weight loss followed by a morerecent 2-week history of constipation, fatigue, and weight gain.Blood pressure is 115/70 mm Hg, pulse rate is 50/min, respirationrate is 14/min, and BMI is 23.3. No proptosis or inflammatorychanges are noted on ocular examination. Neck examination isnormal.
Which of the following is the best next step in management?
A.Measurement of anti-thyroid peroxidase antibodies
B.Measurement of TSH and free T4 levels
C.Thyroid scan and 24-hour radioactive iodine uptake test