Low GFR, and visible and then microscopic blood in urine. Cystoscopy and CT scan clear. Thrombotologist thinks may be a microscopic breakdown of kidneys caused by SLE and recommends a referral to nephrologist. Possible kidney biopsy on cards according to her. Can anyone tell me if lupus nephritis would be unclear from these tests or if there is some other cause? She suggested that my kidneys may not be working at a more microscopic than gross level. I'm back at my GP Tuesday and would like to have some ideas of things we may discuss. Don't much fancy a kidney biopsy, but if it directs the most accurate medication for me then I will have to be brave!