Most conventional thyroid assessments leave much to be desired. Usually the only test performed is a TSH level which is actually a measure of pituitary function, not thyroid. More thorough testing includes free T3 (the active thyroid hormone), free T4 (the main hormone produced by the thyroid gland), thyroid antibodies (an indicator of Hashimoto's thyroiditis and are often related to gluten cross reaction), and reverse T3 (an inactive form of thyroid horme that is usually increased due to acute or chronic stress and which competes for receptors with active T3).
Another test that might be useful would be Iodine. Iodine is essential for the formation of thyroid hormone and is inhibited by bromide, chloride, and flouride which are present in large amounts in our food and environment. The common use among some alternative practitioners of high amounts of iodine like 12.5 mg is irresponsible and potentially dangerous without proper evaluation. People with low iodine levels can usually be repleted safely with amounts near one mg.
Body temperature is a functional sign of thyroid activity. First morning ORAL temperature below 97.7 is a possible indicator of thyroid problems.
Heavy metals such as lead and mercury can interfere with many body functions, including thyroid activity. When other testing fails to detect problems, it is wise to check for heavy metals.
Finally, it is necessary for thyroid hormone production to be dependent on co-factors elements such as selenium, zinc, copper and other trace elements.
Any thyroid evaluation that does not consider all these factors is incomplete.