I m a 50 yr old female. 7 times in the past year I ve had sudden onset of pain low in my back. Each time I was treated for a uti but there is no bacteria, only large amounts of microscopic blood in my urine. I also don t experience common symptoms seen with a uti. No painful urination, burning, or visible blood. Any thoughts?
Hi I am Chat Doctor.  Presence of blood in urine indicates ether infection(which is very common in ladies) or damage to urinary system like renal stones. I suggest you get ultrasound of abdomen to assess the cause of repeated blood in urine.