The potential sources of bias are: 1  Some households use cellphones only and have no landline. 2  Some people may not be contactable by landline from Monday to Friday and may be contactable only by cellphone. 3  Some people use their landlines only to access the Internet, and answer calls only to their cellphones.
A thyroid panel is used to evaluate thyroid function and/or help diagnose hypothyroidism and hyperthyroidism due to various thyroid disorders. The panel typically includes tests for: 1  Thyroid-stimulating hormone (TSH) 2  Free thyroxine (free T4)  Total or free triiodothyronine (total or free T3)
Thyroid hormone blood tests include: Total thyroxine (T4). Most of the thyroxine (T4) in the blood is attached to a protein called thyroxine-binding globulin. Less than 1% of the T4 is unattached. A total T4 blood test measures both bound and free thyroxine.