What Causes The Presence Of RBC In Urine?

I have an rbc of 20-40 in urine. I have had blood in urine on multiple urinalysis, never seen blood in urine had a bladder scope done July 2013 and doc said it looked "boring" in there. Did say I had polyps that may be breaking off thus causing the blood. I also Get UTI's every few months due to position of my lady parts :). I also have Autoimmune Hepatitis and on meds for that for 7 years. I just got these results and haven't heard from my Hepatologist yet, but I have a tendency to freak out if any of results come back wonky. Your thoughts are most welcomed. Thank you