After human blood flows through the kidneys, urine is formed through filtration and reabsorption of the kidneys, which excretes metabolites such as creatinine and urea nitrogen from the blood and retains nutrients such as glucose and protein in the blood, thus maintaining a stable water, electrolyte and acid-base balance in the body. Urine is like a barometer of human health, and changes in urine composition or traits can reflect the health status of the kidneys in time. 1.What is proteinuria? Under normal circumstances, the protein content in urine is very small, and the 24-hour urine protein excretion of normal adults is less than 150mg. When the filtration membrane of kidney is damaged for various reasons, the protein in blood will leak out from the pores of the damaged filtration membrane, and when the amount of leaked protein exceeds the reabsorption capacity of kidney, the protein content in urine will rise and proteinuria will be formed. 2.What are the symptoms of proteinuria? There are usually no symptoms in the early stage of proteinuria, but those who are careful will find more foam in the urine. We do not need to worry too much about foamy urine that is large and easy to break up and dissipate. Such foamy urine can occur when the surface tension of the urine changes due to excessive urination, residual detergent in the urinal, semen or prostate fluid mixed with the urine, or urinary tract infection. Most kidney diseases, especially the milder ones, usually have few symptoms, and many people already have severe kidney failure at the first visit, so kidney disease is a silent killer. When there is persistent small and not easy to dissipate foamy urine, or in severe cases, eyelid or lower limb edema, you should promptly consult a doctor to check the urine routine to see if there is proteinuria for early intervention and treatment. 3.When will proteinuria occur? Once the urine test indicates positive urine protein, is it necessarily caused by kidney disease? No, some people may develop proteinuria under fever, cold or high temperature, after strenuous exercise, or after a change in upright and lying position, etc. This is called physiological proteinuria, which is usually mild and transient without organic kidney damage and is common in young individuals. Proteinuria caused by various primary or secondary kidney diseases is called pathological proteinuria. Primary diseases of the kidney itself such as acute and chronic glomerulonephritis, nephrotic syndrome, and interstitial nephritis can present with proteinuria. People with a history of long-term hypertension, diabetes, systemic lupus erythematosus, etc., will have lesions involving the kidneys over time and develop hypertensive nephropathy, diabetic nephropathy, lupus nephritis, etc. Proteinuria will also occur. 4.How to treat proteinuria? For people who are found to have proteinuria for the first time, they should go to a regular hospital to have a relevant examination for the kidneys. After a full assessment, if the proteinuria is transient, it is suggested to be physiological proteinuria, which usually does not need treatment. If it is determined that the proteinuria is caused by kidney disease, the cause of kidney disease needs to be clarified, and the treatment is different for different causes, and medication should be administered for the cause under the guidance of a doctor. In addition to medication, we should also avoid staying up late and straining, and pay attention to a low salt, low fat, high quality protein diet. Proteinuria is only an important indicator of kidney disease, only one indicator of proteinuria can not reflect the severity of the disease, but should be combined with other tests such as kidney function, biochemical tests, urological ultrasound, etc. to systematically assess the disease. Therefore, once proteinuria is found, you should go to a regular hospital to seek medical advice to clarify the cause of the disease and get early diagnosis and treatment.