Urine routine undamaged erythrocytes 90% usually suggests non-glomerular origin hematuria, which may be caused by urinary tract inflammation, stones, tumors and so on. 1. urinary tract inflammation: when bacteria and other pathogens cause cystitis and urethritis, the mucous membrane and small blood vessels are damaged, which will lead to red blood cells flowing out with the urine, and undamaged red blood cells appear in the urine routine. 2. urinary stones: when stones and ureter rub against each other, it can lead to the destruction of ureter and urethra mucosa, causing tissue damage, red blood cells overflow from the blood vessels into the urethra, and the appearance of undamaged red blood cells in the urine routine. 3. Urinary tumor: when tumor cells invade into the bladder and ureter, it destroys the local tissue cells, causes blood vessel rupture, red blood cells enter into the urethra, and undamaged red blood cells appear in urine routine. And glomerular lesions when red blood cells need to cross the basement membrane, the cell membrane is damaged, as well as the concentration gradient of the renal tubules, resulting in urine routine can appear polymorphic, damaged red blood cells, this is the glomerular origin hematuria. If you find red blood cells in the urine routine, it is recommended to go to the regular hospital in time, complete the examination to clarify the cause of the disease, and then give targeted treatment or treatment under the guidance of the doctor.