For the examination of diabetic nephropathy, patients first need to undergo routine urinalysis and check for the urinary albumin excretion rate. Generally speaking, one characteristic of diabetic nephropathy is the presence of urinary protein. A urinary albumin excretion rate between 20 and 200 µg/min is an important basis for diagnosing early diabetic nephropathy. If a patient’s urinary albumin excretion rate consistently exceeds 200 µg/min, significant diabetic nephropathy is often considered. Of course, this is under the assumption that the patient has had diabetes for at least ten years and has diabetic retinopathy. A kidney biopsy is needed for confirmation. Of course, to assess the impact of diabetic nephropathy on kidney function, blood tests for serum creatinine and urea nitrogen are necessary.