Is It Safe To Postpone Tests Done On Kidneys While Getting Treated For Low Potassium And High Blood Pressure Levels?

I was in er yesterday, for an adrenal gland/low potassium/ high blood pressure issue...I was prescribed losartan and told in VA er to get my kidneys checked out in a week..precaution...my ? Is can this wait until oct 31? I can’t seem to get an appointment until that date... If not I will have to pay out of pocket to be seen....