Proteinuria is caused by the loss of protein in human blood to urine, and the protein is excreted through urine. Patients often have proteinuria because of problems in excretion or absorption. Proteinuria is common in nephritis patients and tumor patients.

Proteinuria is a typical symptom of chronic kidney disease, and the cause of proteinuria is closely related to the barrier function of glomerulus.

Extended data If one of the following items causes proteinuria, it is recommended to do in-depth examination.

Pseudoproteinuria is common in the following situations:

1 urine mixed with blood, pus, inflammation or tumor secretions, menstrual blood, leucorrhea, etc., routine qualitative examination of proteinuria can be positive. A large number of red blood cells, white blood cells and flat epithelial cells can be seen in the sediment of this urine, but there is no cast. After centrifugal precipitation or filtration of urine, the qualitative examination of protein will be significantly reduced or even turned negative.

2. After the urine is left for a long time or cooled, salt crystals can be precipitated, making the urine white and turbid, which is easy to be mistaken for proteinuria, but heating or adding a little acetic acid can make the turbid urine clear to help distinguish it;

3 urine mixed with semen or prostatic fluid, or inflammatory secretions of lower urethra, urine protein reaction can be positive. In this case, the patient has symptoms of lower urinary tract or prostate disease, and sperm and more flat epithelial cells can be found in urine sediment, which can be distinguished;

4 lymphatic urine, which contains less protein, is not necessarily chylous;

When some drugs, such as rifampicin and Shandaonian, are excreted from urine, it can make urine turbid and similar to proteinuria, but the qualitative reaction of protein is negative.

Reference Baidu Encyclopedia-Proteinuria