Many of us have heard of it, and have probably done it, on more than one occasion. Imo, it's a cheap and somewhat effective way to at least see if you might need to add Iodine to your daily health regime.
I'd say, a lot of us have gone with the info. presented from this forum, the Iodine Dr.s suggestions, and people's personal experiences. If you feel you want, should, or need a more complete and accurate test(s) then you'd want to see your Dr. or health professional.