We all know that normal urine is light yellow, and when we find that children have abnormal urine color, such as after the urine color is soy sauce urine or red urine, first do not panic, but first we should distinguish whether it is true hematuria or pseudo hematuria, that is to say, we should exclude some conditions that make the child have a change in urine color but actually not hematuria. Common urine color changes are some of the following: (1) drugs or other causes of red urine, some drugs such as aminopyrine, sodium phenytoin, rifampin, phenol red, etc.; these drugs can cause the child’s urine color is red, or some food, vegetables in the pigment and human metabolism produced by uric acid salts, etc. can make the urine red, but this is not hematuria, at this time to do a urine examination shows that the occult blood test and microscopic examination This is not hematuria, but a urine test showing occult blood test and microscopic examination of red blood cells is negative, so hematuria can be excluded. (2) It is necessary to pay attention to the change of urine color caused by hemoglobinuria and myoglobinuria, such as paroxysmal sleep hemoglobinuria, hemolytic anemia, etc. In this case, the urine can be soy sauce color or coffee color, which is due to hemoglobinuria caused by hemolysis after the destruction of red blood cells, at this time, the urine examination is positive for urine occult blood test, but the microscopic examination does not have red blood cells or occasional red blood cells. Myoglobinuria is an acute destruction of muscle tissue caused by various causes, resulting in rhabdomyolysis and myoglobin excretion from the urine, which can be accompanied by myalgia, muscle swelling, muscle weakness, etc. Myoglobinuria can be pink or dark brown in color. Urine myoglobin test is positive. Myoglobin is soluble in 80% saturated ammonium sulfate solution, while hemoglobinuria is insoluble. It is possible to distinguish between myoglobinuria and hemoglobinuria by this point. In this way, it can help clinicians to judge the condition and diagnose and treat correctly. (3) Non-urinary tract bleeding such as vaginal or lower gastrointestinal bleeding mixed into the urine, menstrual contamination of urine, etc. In this case, the urine occult blood test and microscopic examination of red blood cells are positive, but the blood in the urine is not the red blood cells of urinary tract origin. This requires detailed questioning and physical examination by the receiving physician to identify. Only after the above three conditions are ruled out can the child be diagnosed with true hematuria, which is what we usually call hematuria. What should I do when I know that my child has hematuria? When a child’s hematuria is detected, parents are generally very nervous and anxious to find out the cause. For doctors, after determining that the hematuria is genuine, they need to further determine the source of the hematuria, and the current diagnostic process is: (1) First determine the source of the hematuria: Currently, according to the changes in the morphology of the red blood cells in the urine, the hematuria is divided into two categories: glomerular and non-glomerular hematuria: glomerular hematuria means that the hematuria originates from the glomerulus, and the red blood cells in the urine appear in various sizes and morphological changes, i.e., deformed Red blood cells are predominant; if the microscopic red blood cells have a single morphology and resemble peripheral blood, it is homogeneous hematuria. This is because the hematuria originates from the urinary system below the renal unit and is due to the rupture of blood vessels in the urinary tract, so the red blood cell morphology in the urine is basically normal and homogeneous. Generally speaking, more than 95% of pediatric hematuria is due to diseases of the urinary system itself. The common causes of glomerular hematuria are: primary, secondary and hereditary glomerular diseases, such as acute nephritis, IgA nephropathy, nephrotic syndrome, lupus nephritis, purpura nephritis, hereditary nephritis, etc. Non-glomerular hematuria is common in: urinary tract infection, stones, tuberculosis, hypercalciuria, left renal vein compression or nutcracker phenomenon, congenital urinary tract malformation, drug-induced kidney and bladder injury, tumor, trauma, etc. In addition, it is also seen in systemic bleeding disorders, such as thrombocytopenic purpura, hemophilia, leukemia, malignant histiocytosis, aplastic anemia, etc. If a community health center hospital is not able to perform morphological testing of urine red blood cells, the following methods are also available. (2) The urine triple cup test can be used to locate and analyze hematuria: ① Primary hematuria: It means that hematuria is only seen at the beginning of urination and the lesion is mostly in the urethra. Generally, it is mostly urinary infection and urethral disease. (2) Terminal hematuria: hematuria occurs at the end of urination, and the lesions are mostly in the bladder triangle, bladder neck or posterior urethra, and cystitis is common. ③Total hematuria: It means that hematuria appears in the whole process of urination, and the bleeding site is mostly in the bladder, ureter or kidney. If the hematuria is “total hematuria” and the blood is dark red, it is usually caused by diseases of the kidneys. The identification of the above three types of hematuria is the basis for proper treatment. (3) Laboratory tests: Elevated blood leukocytes are an important clue to the diagnosis of infectious diseases: scarlet fever, urinary tract infections such as acute and chronic pyelonephritis, acute cystitis, urethritis, urinary tuberculosis, fungal infections of the urinary tract, etc. Hematuria with more severe proteinuria is almost always a symptom of glomerular hematuria. High urinary calcium is an important clue that hematuria is caused by hypercalciuria. Tubular patterns in the urine sediment, especially red blood cells, indicate bleeding from the renal parenchyma and are mainly seen in glomerulonephritis. Ultrasound of the urinary system is used to diagnose nutcracker phenomenon (the disease is caused by compression of the left renal vein that travels between the abdominal aorta and the superior mesenteric artery, causing a persistent hematuria called nutcracker phenomenon. Normally, the right renal vein injects directly into the inferior vena cava, while the left renal vein needs to cross the angle formed by the abdominal aorta and superior mesenteric artery to inject into the inferior vena cava. Normally this angle is 45°-60°, but if it is congenitally too small or filled with mesenteric fat, enlarged lymph nodes or peritoneum, it can cause the nutcracker phenomenon. Diagnosis mainly relies on ultrasound, CT or renal venography) and congenital malformations such as congenital polycystic kidney is an important tool, and blood system examination is an important basis for excluding systemic bleeding disorders. (4) Clinical manifestations: The diagnosis of hereditary nephritis is based on age, medical history, concomitant symptoms and signs, and laboratory tests. Hematuria with edema and hypertension is mostly seen in glomerulonephritis; hematuria with renal colic is seen in urinary stones; hematuria with pus and bladder irritation is seen in urinary tract infection; hematuria with renal mass is seen in tumor or polycystic kidney; hematuria with skin and mucous membrane bleeding is seen in hematologic diseases, infectious diseases and other systemic diseases; hematuria with celiac disease is seen in filariasis In conclusion, hematuria is a complex problem with multiple causes. In conclusion, hematuria is a complex problem with multiple causes. For simple microscopic hematuria, which is difficult to be diagnosed at the moment, we can follow up for a long time and go to the hospital for regular review and dynamic observation until the final diagnosis is clear.