Microalbumin Creatinine Ratio

Why this test may be ordered

• To screen for early signs of kidney disease in people with diabetes, high blood pressure, family history of kidney disease, heart disease, or other risk factors.
• To monitor kidney function in individuals already diagnosed with kidney disease.
• To evaluate how well treatment for kidney disease is working.

Preparation and collection

You may need to avoid intense exercise and eating meat for a day before the test. Ask your provider about any medicines or supplements that could affect results.

A urine sample can be collected as a random ('spot') sample, an early morning or timed sample, or a 24-hour collection. The clean catch method may be used for random samples.

According to the source, there is no known risk from providing a urine sample for this test.

Understanding results

The microalbumin creatinine ratio compares the amount of albumin (a protein normally found in blood) to creatinine (a waste product) in your urine. In healthy kidneys, only a trace of albumin passes through the filters. The test result is reported as a ratio, and the interpretation is based on whether the amount of albumin is higher than expected.

• Normal (lower-likelihood): Lower-likelihood of kidney disease. Only a trace of albumin is present, suggesting your kidney filters are working normally. Limitation: Temporary increases from exercise, infections, or inflammation may cause a false-positive result. Next step: If abnormal, your provider will likely repeat the test two more times over the next 3–6 months to confirm.
• Abnormal (higher-likelihood): Higher-likelihood of kidney disease. Abnormal amounts of albumin in urine may be an early sign of kidney damage, but further testing is needed to confirm. Limitation: False-positive results can occur from exercise, fever, or certain medicines. A single abnormal result does not diagnose kidney disease. Next step: Your provider will order additional tests (e.g., eGFR blood test) and repeat the urine test. If two out of three tests are abnormal, early-stage kidney disease is likely. Higher or increasing amounts may indicate more serious kidney disease or a higher risk of heart and blood vessel problems.

• Temporary increases in albumin can occur due to intense exercise, fever, certain medicines, or inflammation, which may cause false-positive results.
• A single abnormal result is not diagnostic; two out of three tests over 3–6 months are needed to suggest early-stage kidney disease.
• Smaller amounts of albumin do not always rule out kidney disease, and results can be affected by muscle density, diet, age, and race.

What to do next

If your result is abnormal, your healthcare provider will likely order additional tests, such as an estimated glomerular filtration rate (eGFR) blood test, and may repeat the urine test two more times over the next 3–6 months to confirm findings.

• What is the purpose of this test for me?
• How should I prepare for the urine collection?
• What do my results mean in the context of my health and risk factors?
• Will I need follow-up tests?

Evidence source

U.S. National Library of Medicine: Microalbumin Creatinine Ratio