Early stage diabetic nephropathy has no symptoms. Over time, the kidney's ability to function starts to decline. Symptoms develop late in the disease and may include:

• Fatigue
• Foamy appearance or excessive frothing of the urine
• Frequent hiccups
• General ill feeling
• Generalized itching
• Headache
• Nausea and vomiting
• Poor appetite
• Swelling of the legs
• Swelling, usually around the eyes in the mornings; general body swelling may occur with late-stage disease
• Unintentional weight gain (from fluid buildup)

The main sign of diabetic nephropathy is persistent protein in the urine. (Protein may appear in the urine for 5 to 10 years before other symptoms develop.) If your doctor thinks you might have this condition, a microalbuminuria test will be done. A positive test often means you have at least some damage to the kidney from diabetes. Damage at this stage may be reversible. The test results can be high for other reasons, so it needs to be repeated for confirmation.

High blood pressure often goes along with diabetic nephropathy. You may have high blood pressure that develops rapidly or is difficult to control.

Laboratory tests that may be done include:

• BUN
• Serum creatinine

The levels of these tests will increase as kidney damage gets worse. Other laboratory tests that may be done include:

• 24-hour urine protein
• Blood levels of phosphorus, calcium, bicarbonate, PTH, and potassium
• Hemoglobin
• Hematocrit
• Protein electrophoresis - urine

A kidney biopsy confirms the diagnosis. However, your doctor can diagnose the condition without a biopsy if you meet the following three conditions:

1. Persistent protein in the urine
2. Diabetic retinopathy
3. No other kidney or renal tract disease

A biopsy may be done, however, if there is any doubt in the diagnosis.