The results of the red blood cell phase are mainly used to determine the source of the patient’s hematuria, whether it is of nephrogenic origin or of postnephrogenic origin. Red blood cell phase: i. If aberrant red blood cells are predominant, consider nephrogenic hematuria. Red blood cells pass through the filtration membrane of the glomerulus, causing destruction of red blood cells and an increase in broken red blood cells. When performing red blood cell phase examination with predominantly aberrant results, further renal puncture biopsy is required to clarify whether the hematuria is of nephrogenic origin. Second, if the hematuria is of post-cardiac renal origin, such as those caused by stones and tumors. The red blood cells have not undergone destruction by the glomerulus and show predominantly homogeneous increase. At this time, the red blood cell phase examination results, suggesting that homogeneity of red blood cells is predominant, temporarily disregard the hematuria of nephrogenic origin, and consider postnephrogenic factors, such as whether combined with infection, whether combined with stones, whether combined with tumors, etc.