Blood in urine is sometimes a sign of a serious disease, so once hematuria is detected, the cause needs to be investigated. There are many causes of hematuria. Most urinary system diseases can show hematuria, such as urinary tract infection, trauma, stones, tumors, etc. Elderly men with prostate enlargement may also show hematuria. Certain internal kidney diseases, such as nephritis, can also manifest hematuria. In addition, certain systemic diseases can also urinate blood, such as blood disorders, coagulation disorders, and cardiovascular diseases. The manifestation of blood in urine may vary from disease to disease. In mild hematuria, it cannot be determined by the naked eye and needs to be confirmed by microscopic examination, while in severe hematuria, the urine is obviously red in color and may also be accompanied by blood clots of different shapes. Some people have blood at the beginning of urination, others, bleeding at the end of urination, while others urinate blood throughout the entire urination. The doctor can make a rough assessment of the likely location of the bleeding based on these characteristics. Some urological tumors, such as bladder cancer, may present as intermittent blood in the urine, so the fact that the hematuria resolves on its own should not be overlooked for screening. Screening for the cause of hematuria is sometimes complicated. After a urinary tract infection is ruled out, imaging is usually required, often with ultrasound or CT scan. When imaging cannot determine the cause, or when a tumor in the urinary tract is suspected, a cystoscopy is often recommended by your doctor. Cystoscopy can help determine if there are any bleeding lesions in the urethra and bladder, or to narrow the examination by bleeding from the ureteral opening.