What is the microalbumin (Microalbuminuria) level?

From the Guidelines

Microalbumin levels should be measured annually in patients with diabetes, hypertension, or other kidney disease risk factors, with normal levels being less than 30 mg/24 hours or less than 20 mg/L in a spot urine sample, and levels between 30-300 mg/24 hours indicating microalbuminuria, suggesting early kidney damage. According to the most recent guidelines, microalbuminuria is a strong predictor of cardiovascular risk and kidney disease progression 1. The European guidelines on cardiovascular disease prevention in clinical practice recommend measuring microalbuminuria from spot urine samples and treating patients with microalbuminuria and proteinuria with an ACE inhibitor or angiotensin II receptor antagonist regardless of baseline BP 1.

Some key points to consider when interpreting microalbumin levels include:

• Normal microalbumin levels are less than 30 mg/24 hours or less than 20 mg/L in a spot urine sample
• Levels between 30-300 mg/24 hours indicate microalbuminuria, suggesting early kidney damage
• Levels above 300 mg/24 hours indicate macroalbuminuria and more significant kidney disease
• Microalbuminuria is a strong predictor of cardiovascular risk and kidney disease progression
• Treatment focuses on controlling underlying conditions like diabetes and hypertension, often with medications such as ACE inhibitors or ARBs, and lifestyle modifications including reducing sodium intake, maintaining healthy weight, exercising regularly, and avoiding nephrotoxic medications 1.

It is essential to note that microalbuminuria can be measured from spot urine samples, and patients with microalbuminuria and proteinuria should be treated with an ACE inhibitor or angiotensin II receptor antagonist regardless of baseline BP 1. The Steno-2 study demonstrated the benefits of intensified treatment, including ACE inhibitors or ARBs, in patients with type 2 diabetes and microalbuminuria 1.

In terms of screening, the current recommendations include screening for albuminuria in patients with diabetes or evidence of kidney disease, but not the general population 1. However, the European guidelines recommend measuring microalbuminuria in patients with diabetes, hypertension, or other kidney disease risk factors, typically annually 1.

Overall, microalbumin levels are a valuable tool for early detection of kidney damage and cardiovascular risk, and regular testing and treatment can help prevent progression of kidney disease and reduce cardiovascular risk 1.

From the Research

Definition and Importance of Microalbumin Level

• Microalbuminuria is defined as a persistent elevation of albumin in the urine of >30 to <300 mg/d (>20 to <200 microg/min) 2
• The presence of microalbumin in the urine of persons with type 2 diabetes is an important early signal heralding the onset of systemic vasculopathy and associated target organ damage to the brain, the heart, and the kidneys 3
• Microalbuminuria is an established risk marker for the presence of cardiovascular disease and predicts progression of nephropathy when it increases to frank microalbuminuria >300 mg/d 2

Measurement and Screening of Microalbumin Level

• The morning spot urine test for albumin-to-creatinine measurement (mg/g) is recommended as the preferred screening strategy for all patients with diabetes and with the metabolic syndrome and hypertension 2
• Microalbuminuria should be assessed annually in all patients and every 6 months within the first year of treatment to monitor the impact of antihypertensive therapy 2

Treatment and Management of Microalbumin Level

• Therapeutic strategies to facilitate better blood pressure control and reduce microalbuminuria likely will prove to be the most effective way to retard not only the progression of renal disease but also cardiovascular disease 3
• Angiotensin-converting enzyme (ACE) inhibitors and angiotensin II (ATII) receptor blockers have similar efficacy in treating diabetic microalbuminuria, and the combination of the two drugs does not add any further benefit 4, 5
• ACE inhibitors and ARBs have similar effects on microalbuminuria in normotensive patients with type 2 diabetes mellitus, and combination therapy does not provide additional benefit 5
• However, given the equal outcome efficacy but fewer adverse events with ARBs, risk-to-benefit analysis in aggregate indicates that at present there is little, if any, reason to use ACE inhibitors for the treatment of hypertension or its compelling indications 6