Hematuria is a common symptom of pediatric urological disorders. The number of red blood cells in normal human urine is only 0-2/high magnification field. Hematuria refers to a higher than normal number of red blood cells in urine and is divided into microscopic hematuria and naked eye hematuria, the former is found only under the microscope with increased red blood cells. Take 10mu of fresh clean middle urine (early morning is good), centrifuge at 1500 rpm for 5 minutes, discard the supernatant, mix 0.2m of the residue at the bottom of the tube and then smear it for microscopic examination, red blood cells >3/high magnification field under high magnification, or urine sediment red blood cell count >8×10/L (8000/ml) is microscopic hematuria. The naked eye can see that the urine is “meat wash” color or blood, called “naked eye hematuria”. Generally when 1000m of urine contains 0.5ml of blood, it can be seen as carnal hematuria, the color of carnal hematuria is related to the pH of urine, neutral or weakly alkaline urine is bright red or meat wash-like, acidic urine is strong tea-like or sooty water-like. The causes of blood are many, and various pathogenic causes of impaired glomerular base integrity or increased permeability, increased intracapillary pressure, damage to the urethral mucosa, and systemic coagulation mechanism barriers can lead to hematuria 1, kidney disease: various primary glomerular diseases: acute and chronic glomerulonephritis, IgA nephropathy, etc. 2, urinary tract diseases: (1) infection: cystitis, urethritis, tuberculosis. (2) Stones: tubal stones, bladder stones. (3) Tumors, polyps, diverticula, foreign bodies, etc. 3. Systemic diseases: (1) Bleeding disorders: diffuse intravascular coagulation, thrombocytopenic purpura, hemophilia, leukemia, etc. (2) Cardiovascular diseases: congestive heart failure, infective endocarditis. (3) Infectious diseases: scarlet fever, typhoid fever, infectious mononucleosis. (4) Systemic diseases: systemic lupus erythematosus, allergic purpura, etc. (5) Allergic diseases: dietary allergy, such as milk or pineapple allergy. (6) Nutritional diseases: vitamin C deficiency, vitamin K deficiency (7) Other diseases: such as hereditary capillary dilation, transient hematuria caused by strenuous exercise, idiopathic hypercalcemia, etc. How to determine true hematuria and pseudohematuria? The diagnosis of true hematuria and pseudohematuria hematuria should first exclude the following conditions that can produce pseudohematuria: red color caused by the intake of large amounts of artificial color (such as aniline) food (such as honey, blackberries, beets) or drugs (such as rhubarb, rifampin, benzoin sodium); hemoproteinogen or myoglobin: uric acid salts in the urine of newborn babies can make the diapers red; blood stool contaminated with menstrual blood.