What kind of blood tests must be done after ovarian polycistosis is found by ultrasound?

May not need any: Pcos or polycystic ovarian syndrome is quite common, much more so in obese females. I assume you saw doc, got evaluated and suspected pcos which ultrasound confirmed it? If so, likely no further lab/testing needed. If ultrasound findings are concerning, some tumor marker testing could be done, but i would recommend consulting your doc first. Good luck.