Determining the source of hematuria is important for clarifying the etiology and treatment. For simple erythrocyte urine, the urine can be divided into glomerular-derived erythrocytes and non-glomerular-derived erythrocytes by applying phase contrast microscopy to observe the red cells in the urine. Of course, other tests are also important, such as ultrasound, kidney function, etc. Method: Morning urine is taken to observe the size and shape of red blood cells in urine through urine phase contrast microscopy. The clinical significance: the red blood cells show polymorphic changes of different sizes and shapes, or appear gourd-shaped, bagel-shaped, strawberry-shaped and broken red blood cells, suggesting hematuria caused by glomerular diseases such as IgA nephropathy; those with similar size and normal or basically normal appearance suggest hematuria caused by non-glomerular diseases, which can be seen in surgical hematuria such as renal tumors, stones, tuberculosis and bladder diseases. As confirmed by surgical treatment and renal biopsy, phase contrast microscopy is applied to distinguish glomerular-derived from non-glomerular-derived urinary red blood cells, with a compliance rate of more than 90%. The volume of red blood cells can also be measured.