I have a family history of thyroid issues. both my mother & sister take medication for it. how often should i be re-tested? dr. says i don't have it.

Thyroid problems are: more common in women, especially with increasing age and those with family members who have thyroid issues. In my practice I generally screen with a TSH about yearly or when my patients have signs or symptoms suggesting possible thyroid disorder. If the TSH is out of range or borderline (high or low normal) I will check the free T4 and free T3 (liothyronine). If abnormal, some other tests may be required.