The cost of thyroid function tests varies slightly from one level of hospital to another. A triple test is usually about$120. The triple test includes thyrotropin, free thyroxine, and free triiodothyronine. The cost of triple A is about$180, which includes thyroxin and triiodothyronine. Thyroid 7 is thyroid 5 plus thyroglobulin antibodies and thyroid peroxidase antibodies, and generally costs about$280. For thyroid function tests, both fasting and mealtime blood draws are possible. Three days before the test it is recommended to eat lightly, avoid overeating, keep your mood relaxed and ensure sufficient sleep.