Urine protein is qualitative diagnosis, 24-hour urine protein quantification is quantitative diagnosis. Generally speaking, normal people with negative urine protein usually do not need to do 24-hour urine protein quantification; if patients with kidney disease, even if the urine protein is negative, it is still recommended to do 24-hour urine protein quantification. Under normal circumstances, when plasma flows through the glomerulus, only a small amount of proteins with small relative molecular mass passes through the glomerular filtration membrane, and proteins with medium and large relative molecular mass cannot be filtered. Most of the protein in the original urine is reabsorbed by the renal tubules, and the urine contains only a very small amount of protein, which cannot be measured by conventional chemical characterization methods. When the urine protein content > 150mg/24h or urine protein concentration > 100mg / L, the routine chemical characterization of the test was positive, known as proteinuria, the normal population urine protein negative generally do not need to do 24-hour urine protein quantification. Kidney disease such as nephritis, nephrotic syndrome patients, that is, urine protein negative, or recommended to do 24-hour urine protein quantification. If you have abnormal urine protein or 24-hour urine protein quantification, you should go to the hospital in time to find out the reason and treat under the guidance of professional physicians.