Any ideas why is it that i have blood in my urine and docs don't know why?

Blood in urine: If there is a trace of blood and nothing else abnormal, then blood is entering your urine in some way. Are there symptoms like burning with urine, flank pain, recent infection, etc? In females this is common with recent period. See your doctor for further follow up as this needs to be looked at in a clinical context to be sure everything is good.