The preliminary judgment of hematuria can be made based on the characteristics of the hematuria itself, its relationship to the course of the disease and the morphology of the red blood cells in the urine. (1) Characteristics of hematuria itself: Upper urinary tract bleeding refers to bleeding above the ureter, where blood is evenly mixed with urine and is dark red in color. Lower urinary tract bleeding is mostly due to bladder and prostate disease, bright red in color, often with blood clots. Regardless of the bleeding in the upper or lower urinary tract, the blood and urine are visible as a cloud when shocked and a layer of red precipitation is visible after placement. (2) The relationship between blood and urinary process: apply the “three cups test” to judge, take three colorless, clean glass cups, during the process of continuous urination, respectively retain the urine at the beginning, middle and end of urination. If the hematuria is evenly distributed in the three glasses, it is called full hematuria, which is seen in upper urinary tract or bladder disease; the hematuria in the first glass is initial hematuria, which is seen in urethral disease; the hematuria in the third glass is final hematuria, which is seen in bladder neck, triangle or posterior urethral disease. (3) Urine red blood cell morphology: applying phase contrast microscopy to observe the morphology and size of red blood cells and the uniformity of hemoglobin distribution within red blood cells, hematuria can be classified as homogeneous or polymorphic. Homogeneous erythrocytes are similar to those in the surrounding blood, equal in size, round or flat disk-shaped, with uniform distribution of intracellular hemoglobin, mostly caused by non-glomerular diseases, such as renal tumors, stones, tuberculosis and other surgical diseases, also known as surgical hematuria. Polymorphic erythrocytes with unequal size, variable morphology and uneven distribution of hemoglobin are caused by glomerular diseases and are also called medical hematuria. This test is often used as a primary screening method for the diagnosis of hematuria.