Protein in urine (proteinuria or microalbuminuria) is an abnormally high amount of protein found in a urine sample. A test to analyze the content of your urine (urinalysis) checks for several substances in your urine, including protein.

Your kidneys filter waste products from your blood while retaining components your body needs — including proteins. However, some diseases and conditions can allow proteins to pass through the filters of your kidneys, causing protein in urine.

Low levels of protein in urine are normal. Temporarily high levels of protein in urine aren't unusual either, particularly in younger people after exercise or during an illness. Protein in urine discovered on a microalbumin test may often be the earliest sign of diabetic kidney damage.

May. 21, 2011