When is a microalbumin test ordered for patients with diabetes?

Microalbumin Testing in Diabetes Management

Microalbumin testing should be performed annually in all type 2 diabetic patients starting at diagnosis and in type 1 diabetic patients after 5 years of diabetes duration to screen for early kidney damage. 1, 2

Definition and Significance

Microalbuminuria refers to urinary albumin excretion of 30-299 mg/24 hours or an albumin-to-creatinine ratio (ACR) of 30-299 mg/g creatinine. It represents an early marker of diabetic nephropathy and vascular dysfunction 1.

The clinical significance of microalbuminuria includes:

• Early indicator of incipient diabetic nephropathy
• Predictor of progression to overt nephropathy
• Marker of increased cardiovascular risk
• Indicator of endothelial dysfunction

Screening Protocol

When to Screen:

• Type 1 diabetes: Begin screening after 5 years of diabetes duration, then annually 2, 1
• Type 2 diabetes: Begin screening at diagnosis, then annually 2, 1

Preferred Testing Method:

The preferred screening method is measuring the albumin-to-creatinine ratio (ACR) in a random spot urine collection 2, 1:

Category	ACR (mg/g creatinine)
Normal	<30
Microalbuminuria	30-299
Macroalbuminuria	≥300

Confirming Diagnosis:

Due to variability in urinary albumin excretion, at least 2 of 3 specimens collected within a 3-6 month period should be abnormal before confirming a diagnosis of microalbuminuria 2, 1.

Factors Affecting Test Results

Several factors can cause temporary elevation in urinary albumin excretion 2, 1:

• Exercise within 24 hours
• Urinary tract infections
• Fever
• Congestive heart failure
• Marked hyperglycemia
• Marked hypertension
• Menstruation

Management After Detection of Microalbuminuria

Once microalbuminuria is detected, implement the following interventions:

1. Optimize glycemic control: Target HbA1c <7% 1, 2

2. Blood pressure management:

   • Target <130/80 mmHg 1
   • Use ACE inhibitors or ARBs as first-line therapy 2

3. Consider medication adjustments:

   • For type 2 diabetes: Consider SGLT2 inhibitors or GLP-1 receptor agonists 1
   • If ACE inhibitors are not tolerated, substitute with ARBs 2

4. Dietary modifications:

   • Protein restriction to approximately 0.8 g/kg body weight per day 2, 1
   • Low-salt diet 1

5. Monitoring:

   • Check ACR every 3-6 months to assess treatment response 1
   • Monitor serum creatinine and potassium when using ACE inhibitors or ARBs 1, 2
   • Annual assessment of eGFR 1

Nephrology Referral Criteria

Consider referral to a nephrologist when 1, 2:

• eGFR has fallen to <60 ml/min/1.73 m²
• Difficulties occur in management of hypertension or hyperkalemia
• Uncertain etiology of kidney disease
• Rapidly progressing kidney disease
• Urgent referral if eGFR <30 ml/min/1.73 m²

Common Pitfalls to Avoid

1. Failing to confirm microalbuminuria: A single positive test is insufficient; confirm with 2-3 specimens over 3-6 months 2, 1

2. Ignoring factors that temporarily affect results: Exercise, infections, and poor glycemic control can cause transient elevations 2, 1

3. Delaying treatment after confirmation: Once confirmed, promptly implement interventions to prevent progression 1, 3

4. Inadequate monitoring: Regular follow-up of ACR, eGFR, and electrolytes is essential to assess response to therapy 1

5. Missing the cardiovascular risk implications: Microalbuminuria is not just a renal marker but also indicates increased cardiovascular risk 4, 3

By implementing systematic screening and appropriate management of microalbuminuria, progression to overt nephropathy can be delayed or prevented, ultimately improving both renal and cardiovascular outcomes in patients with diabetes.