A patient's urine shows the presence of proteins. This could be due to error in

The first step in urine formation is Ultrafiltration. This takes place in the glomerulus. The term means even the smallest particles are filtered in the bowman's capsule. All the substances are filtered except for the plasma proteins. Thus if the urine of the person shows presence of proteins, it is due to kidney damage or some error in the ultrafiltration process.