I think that it is necessary to test also for T3 & T4 and maybe Free T3 & Free T4 as well to get an accurate picture of how a thyroid is functioning. The TSH may look to be in "normal range" and may not show as much as those other tests. Have a look in the thyroid forum here for more information.

Of course if your TSH shows low, then the Dr. will know that something needs to be done.