People with proteinuria have unusually high amounts of protein in their urine. The condition is often a sign of kidney disease. Your kidneys are filters that don’t usually let a lot of protein pass through. When kidney disease damages them, proteins such as albumin may leak from your blood into your pee. You can also have proteinuria when your body makes too much protein. Kidney disease often has no early symptoms. Protein in your pee might be one of the first signs. Your doctor may spot proteinuria on a urine test during a routine physical. Everyone has protein in their blood. The main protein in your blood is called albumin. Proteins have many important jobs in your body, such as helping to build your bones and muscles, prevent infection and control the amount of fluid in your blood.