Diabetes-induced kidney damage primarily affects the glomeruli, leading to hardening and narrowing of glomerular blood vessels. Clinically, this is manifested by proteinuria, starting with small amounts of urinary protein and progressively increasing to large amounts, ultimately causing renal failure. Generally, hematuria is rare during the course of diabetic nephropathy. If a patient with diabetic nephropathy experiences hematuria, and the cause is unexplained, it is generally recommended that the patient undergo procedures such as a kidney biopsy to further clarify the cause. It is possible that the patient may have other forms of glomerulonephritis, or an ultrasound of the urinary system should be performed to rule out common causes of blood in the urine, such as urinary system stones or tumors.