Nephrologists routinely measure protein levels in kidney patients' blood and urine. The Whether the levels are high or low determines whether other diagnostic procedures are indicated, how aggressively to treat the disease and what nutritional changes are required. Understanding the difference between measuring protein in the blood and urine and what the results mean is important for all kidney patients.
High Urine Protein
High urine protein is a red flag for kidney disease. Healthy kidneys clean the blood and excrete the impurities into the urine. Large molecules like proteins remain in the blood. For reasons that are unclear, the filters of inflamed kidneys allow this protein to spill into the urine. Since high urine protein can damage the filters, also called glomeruli, in the kidney, doctors try to control protein with diet and drugs.
Low Albumen
Large amounts of protein in the urine suggest that levels of protein in the blood are lower than normal. Doctors measure a protein in the blood called albumen. Lower-than-normal albumen levels are called hypoalbuminemia. Low albumen levels suggest that other proteins such as enzymes, hormones and immunoglobulins are also being lost into the urine.
Nephrosis
Very high urine protein is called nephrosis. Patients who lose more than 3.0 to 3.5 g of protein in a 24 hour period, or have a protein/creatinine ratio higher than 3.0 or 3.5 mg/dl are said to be nephrotic. Fluids move from the blood into the tissues. The kidneys try to compensate by retaining salts and other fluids, which is why edema is a common problem in these patients.
Treatment
High urine protein and the corresponding low albumen are often treated with angiotensin converting enzyme inhibitors, also known as ACE inhibitors. Although these drugs are usually used to lower blood pressure, they also help prevent the kidneys from spilling protein into the urine. Prednisone is often prescribed if the patient is nephrotic.
In addition to drugs, nephrologists may also recommend a low protein diet. These diets are not for all kidney patients so never start one on your own without consulting your nephrologist.
