Chronic kidney disease is defined as kidney damage or decrease in kidney function lasting for more than 3 months. Since chronic kidney disease is a chronic disease, it means that this disease is the same as hypertension, diabetes and other chronic diseases, which cannot be cured with the current medical technology that we already have. Therefore, do not believe in the misleading of some advertisements, not to mention the loss of money, inappropriate treatment may even accelerate the progress of kidney disease. Indicators of kidney damage include the presence of red blood cells or protein in the urine, etc., or ultrasound findings such as kidney stones, cysts, occupying lesions or other structural abnormalities. There are other rare conditions that are also thought to indicate the presence of kidney damage, such as a kidney after surgery or a transplant. The easiest way to check for the presence of red blood cells in the urine is with a routine urine test strip, which is considered to have red blood cells in the urine if it is positive for occult blood. However, this method of confirming the presence of red blood cells in urine has a high false positive rate, with some experts estimating a false positive rate of up to 80%, meaning that only 20 out of 100 urine specimens identified as having red blood cells in urine by the urine test strip actually have red blood cells. There are many reasons for false positives, and as patients, we don’t need to ask what causes false positives, we just want an accurate result, and that is to do a microscopic examination of the sediment in the early morning fasting urine. The easiest way to check for the presence of protein in the urine is also a routine urine test strip. If the urine test strip checks positive for protein, regardless of how many plus signs are positive, you can be sure that this test is positive for urine protein. Drinking a lot of water leads to increased urine volume and dilution of the urine, and if there are few red blood cells and protein in the urine, the urine routine test strip is negative for red blood cells and albumin. For example, a patient is ready to have a routine urine test tomorrow morning, but has drunk a lot of soup, drinks or water this evening and holds the urine until tomorrow morning, leaving it for the test. This urine has been severely diluted and may result in a false negative (false negative means that the test is negative when it should have been positive). The correct approach is to not consume large amounts of liquid food or drink the first night of the test, to urinate and discard before coming to the hospital the morning of the test, and to retain urine only after coming to the hospital. To avoid contamination by vulvar secretions, the routine urine test is done by retaining mid-stage urine. Mid-stage urine is the urine that is picked up with a small cup during urination; it is not the urine that is first stopped for a while and then followed by urination after setting up the cup. The glomerular filtration rate is generally used to indicate kidney function. The easiest way to measure the glomerular filtration rate is to draw blood to test the blood creatinine and then use the formula to calculate the glomerular filtration rate. A glomerular filtration rate of less than 60 ml/min/1.73 m2 is defined as decreased renal function. The finding of proteinuria, hematuria or decreased renal function in one test does not confirm the diagnosis of chronic kidney disease. A re-test at an interval of 3 months is required and at least one of these three remains positive to diagnose chronic kidney disease. That is, at least one of the three criteria is problematic and persists for more than 3 months to establish the diagnosis of chronic kidney disease. In some cases, it is not necessary to wait for 3 months before retesting. Combined with past medical history (kidney transplant, chronic nephritis, etc.), pre-existing symptoms (edema, etc.) or other tests (blood tests, ultrasound, etc.), a single test may be able to confirm the diagnosis of chronic kidney disease and require scheduling further tests and treatment; or a single test may determine that the patient has acute kidney injury and needs to be treated as soon as possible or even as an emergency.