Often patients with positive results of urine occult blood in routine urine tests look for me to prescribe drugs or seek treatment recipes, and in the face of them, I can only smile bitterly with helplessness. People’s life today is getting faster and faster, and they also want to see the doctor as fast as possible, which is obviously not in line with scientific common sense. Urine occult blood test is just a very simple test. It is based on the simple principle that if iron-containing components are found in the urine, the presence of red blood cells can be inferred. Although this method is simple and does not require special equipment, a piece of test paper can be used, but its specificity is too outrageous. The reason why I don’t pay much attention to this test is that it is too much influenced by external factors, especially diet. If you have taken iron-containing drugs, animal blood, animal liver, lean meat, and a lot of green vegetables or supplementation with vitamin C supplements before the test, it may cause a positive urine occult blood test result, and the more you eat, the stronger the positive degree. Therefore, urinary occult blood does not necessarily mean that there is blood in the urine. Therefore, I do not recommend this test repeatedly for patients who have been diagnosed with kidney disease. When a patient is first diagnosed with positive urine occult blood, a microscopic examination of the urine sediment or urine must be done to visually see if there is a real red blood cell component in the urine or not: the diagnosis of microscopic hematuria can only be confirmed by seeing 1-3 red blood cell counts per high magnification field under the microscope. After red blood cells are found in the urine it is necessary to further observe its morphology. Only when a large number of red blood cells of various morphologies are found in the urine does it have clinical significance for the diagnosis of nephritis.