I have had microscopic hematuria since I went thru menopause. It is classified as "idiopathic - no known cause." I have had the following tests: cystoscopy; MRI with contrast; CT scan with contrast; renal ultrasound; urine cytology, you name it. It has been attributed to very low estrogen. I have always been on the thin side and have refused any kind of hormone therapy. All of my diagnostic tests have come back normal. Microscopic hematuria (idiopathic) is very common in post menopausal women. I hope this helps.