Diabetic nephropathy is the commonest cause of end stage renal disease in the western world. Diagnosis is made on a clinical and biochemical grounds, typically the presence of diabetes for 10-20 years or more, a progressive deterioration in renal function associated with worsening proteinuria, no haematuria, and usually other microvascular complications such as retinopathy or neuropathy. The mainstay of management is anti-hypertensive therapy with ACE-inhibitors and/or angiotensin receptor blockers. Eventually dialysis or transplantation are necessary in a proportion of cases.

Urine dipstick analysis

This is a very cheap, quick and easy way to detect overt proteinuria and therefore should be performed at every annual review. In addition, if provides information on whether there is likely to be any urinary tract infection (important to exclude as a cause of proteinuria) and haematuria. Haematuria is not a normal feature of diabetic nephropathy and its presence should alert the physician to the possibility of an alternative diagnosis.

  What is the urinary albumin:creatinine ratio?

The ablumin:creatinine ratio (ACR) is a way of detecting proteinuria before it becomes apparent on dipstick testing. It is performed on a spot urine sample and therefore dispenses with the necessity to perform a 24 hr urine collection. Values of less than three are normal and greater than three, especially if persistent, indicate early nephropathy (so long as other potential causes such as urinary tract infection have been excluded).

Renal ultrasound scan

Assessing renal size and ruling out obstruction or other structural lesions are important steps in making a diagnosis of diabetic nephropathy.

What other investigations should be arranged?

1. Urinalysis to screen for haematuria and if haematuria is present (in the absence of infection) then urinary microscopy should be performed to look for other features of active sediment such as casts. If these are present, they indicate a glomerular lesion such as glomerulonephritis.

2. Consideration should be given to requesting other blood tests such as protein strip, immunoglobulins, complement levels, CRP, ESR, calcium and auto-antibodies if there are clinical indications to do these.

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