Excess protein in the kidney is called proteinuria. This is tested in the urine and can also be called albuminuria or urine albumin. Most proteins are too big to pass through the glomeruli, or the kidney filters. When these filters are damaged, the proteins show up in the urine. High levels of protein in the urine are usually an indication of kidney damage or disease.
People with diabetes, high blood pressure or inflammatory diseases such as lupus, rheumatoid arthritis, Hodgkin's disease and leukemia are more at risk for developing kidney disease or chronic renal failure. Managing the other diseases that increase the risk for kidney disease can significantly lessen the risk.
Most people do not suspect kidney disease until their urine is tested. Other potential indicators include foamy urine and swelling of the hands, feet, abdomen or face. The spilling of protein into the urine affects the body's ability to balance fluids, thus causing a build-up of fluids, which is called edema.
Blood and urine tests are needed to diagnose kidney disease. A doctor can calculate a glomerular filtration rate based on the blood creatinine, age, race and gender to assess the degree of disease progression. Creatinine is a waste product from muscle activity that can build up in the bloodstream if the kidneys are not functioning properly. Blood urea nitrogen is another waste material from the breakdown of protein in foods and by metabolism. This can be affected by diet but usually increases because of decreased kidney function. Many medications, including antibiotics, can interfere with diagnostic test results. Dehydration and urinary tract infection can also disrupt tests.
The severity of damage to the kidneys dictates the treatment plan. Medication therapies would be started immediately. Diet might be modified to include less protein. There might be additional restrictions on sodium, potassium, phosphorus and other minerals to place less demand on the filtering processes the kidney controls. In end-stage kidney disease, organ transplant and/or regularly scheduled dialysis might be required to take over the normal kidney function.
Low levels of protein in the urine can be normal, especially in younger people after exercise. There also can be a temporary rise in protein levels with exposure to temperature extremes, emotional stress, fever and strenuous exercise.