Dialysis - Need Some Answers

Can someone tell me if kidney disease is reversible.  What are the tests that are done to determine the need (or lack thereof) for dialysis?

I am 70 and have had high blood pressure for the past 2 yrs., since my husband passed away.  The meds I've been on have not been very good at helping to lower my blood pressure.

I'm a bit confused, and a little scared, and would appreciate some answers if someone has some.

Thank you

K.K.