Protein in the urine can be present for as many as five to 10 years before any symptoms appear. However, foamy urine, fluid retention and swelling (edema) are sometimes seen in patients with proteinuria. However, edema often occurs only in the latter stages of proteinuria.

As more and more protein is leaked into the urine, the amount of protein in the blood drops below the level needed for good health. Albumin (the most common protein found in urine) is necessary for blood to retain water within the arteries and capillaries. As the albumin level drops in the blood – because it is being leaked out through urine – water can accumulate in the tissues and cause swelling in the chest, legs or abdomen.

Although undetectable in normal urine tests, the beginning stage of proteinuria (microalbuminuria) frequently appears without any outward signs or symptoms. Protein in the urine may be present for several years before other, concurrent indicators of diabetic nephropathy begin to appear, such as high blood pressure, diabetic retinopathy or vascular (blood vessel) changes.