In healthy people, the amount of protein in the urine is very small (less than 150 mg per day) and the qualitative protein test is negative. When the amount of protein in urine increases beyond 150 mg/d, it can be detected by ordinary routine urine examination and is called proteinuria. If the urine protein content is ≥3.5g/24h, it is called massive proteinuria and is commonly seen in patients with nephrotic syndrome. Proteinuria is a typical symptom of chronic kidney disease. When proteinuria is present, it can be judged as a clinical symptom caused by kidney damage through ultrasound, kidney function tests, and routine urine tests, in addition to excluding other causes such as physiological factors and postural factors. What diseases will cause proteinuria? Proteinuria is a common clinical manifestation of various kidney diseases, primary glomerular diseases such as acute nephritis, nephrotic syndrome, chronic nephritis including IgA nephropathy, membranous nephropathy, membranous value-added nephritis, thylakoid proliferative nephritis, etc. Secondary glomerular diseases such as hypertensive kidney damage, diabetic nephropathy, systemic lupus erythematosus, purpura nephritis, desiccation syndrome, rheumatoid arthritis, multiple myeloma, hepatitis B kidney damage, etc. In addition, proteinuria can also occur in various interstitial nephritis such as pyelonephritis, gout kidney, drug-induced kidney damage, etc. Proteinuria can also occur in some cases such as strenuous exercise, long-distance march, high temperature environment, fever, cold environment, mental stress, congestive heart failure, etc. However, most of these proteinuria are transient in nature. What does the presence of protein in the urine mean? The clinical significance of proteinuria is very complex, and persistent proteinuria is often seen clinically to indicate substantial damage to the kidneys. When proteinuria changes from more to less, it can either reflect an improvement in kidney disease, or it can be a sign of worsening kidney function due to a decrease in filtered protein as a result of fibrosis in most glomeruli. Therefore, to determine the severity of kidney disease, it is important to consider the amount and duration of protein in the urine, as well as the systemic condition and kidney function tests. What is the danger of proteinuria? Long-term persistent proteinuria will lead to hypoproteinemia and serious edema. The biggest harm of proteinuria is its toxic effect on glomerular thylakoid and proximal tubular cells, and persistent proteinuria will lead to glomerulosclerosis and eventually renal failure. Numerous clinical data show that patients with nephrotic syndrome and persistent proteinuria have a poor prognosis. In focal glomerulosclerosis, membranoproliferative glomerulonephritis, membranous nephropathy, IGA nephropathy, diabetic nephropathy and chronic renal transplant rejection, proteinuria is a significantly unique determinant of kidney disease progression and increased morbidity and mortality. Indeed remission of these diseases and reduction in urinary protein excretion, either spontaneously or as a result of aggressive treatment, may improve survival. What should I do if I have proteinuria? A. Timely examination and treatment at nephrology specialists Urine protein examination can be divided into qualitative examination, quantitative examination and special examination, the ordinary routine urine examination includes qualitative examination, and the best qualitative examination is morning urine, which is the most concentrated and can exclude somatic proteinuria. In order to make a clear diagnosis, patients with proteinuria often need to undergo blood tests and imaging tests such as ultrasound and CT in addition to urine tests, and some patients need to undergo kidney puncture to make a clear diagnosis. The quantitative urine protein examination is more accurate for the observation of the condition and efficacy. 24-hour urine protein quantitative retention method: 1, active urination at 8:00 am on the day of retention, this time the urine is produced before 8:00 am and should be discarded. 2.After 8 o’clock to 8 o’clock of the next day, each urine discharge in 24 hours should be kept in a clean container. 3.The next day at 8:00 should also be active urination, this time the urine is produced before 8:00 and must all be left behind. 4.Collect and stir the urine of 24 hours and record the total amount. 5.Take out 10 ml of the mixed 24-hour urine and send it to the laboratory for 24-hour urine protein quantification, and inform the laboratory doctor of the total urine volume. Notes for urine protein quantification retention: (1) In hot climate, put preservatives in the urine to avoid decomposition of urine sugar, fermentation and bacterial reproduction, thus affecting the accuracy of the results. (2) It is more ideal to keep the urine in the refrigerator. (3) There is a relatively simple way to preserve urine: just cover the container where you put the urine tightly, put it in cold water (note: change the water every 2 to 3 hours), and then put it in a relatively cool toilet. It is not necessary to put preservatives or put it in the refrigerator. (4) Place the collected urine in a cool place to prevent bacteria from invading and multiplying, so as not to affect the laboratory results. Most of the kidney disease with proteinuria is a chronic process that keeps developing, and once proteinuria appears, it often requires a long time of treatment. Through the combined application of Chinese and Western medicine, proteinuria can be relieved or completely controlled in most patients, and the continuous progress of the disease can also be controlled.