Microalbuminuria test

Definition

This test looks for a protein called albumin in a urine sample.

Albumin can also be measured using a blood test or another urine test, called the urine protein test.

Alternative Names

Diabetes - microalbuminuria; Diabetic nephropathy - microalbuminuria; Kidney disease - microalbuminuria; Proteinuria - microalbuminuria; Moderately increased albuminuria

How the Test is Performed

You will usually be asked to give a small urine sample while at your health care provider's office.

In rare cases, you will have to collect all of your urine at home for 24 hours. To do this, you will get a special container from your provider and specific instructions to follow.

To make the test more accurate, urine creatinine level may also be measured to allow calculating the ratio of albumin to creatinine in your urine. Creatinine is a chemical waste product of creatine. Creatine is a chemical made by the body that is used to supply energy to muscles.

How to Prepare for the Test

No special preparation is necessary for this test.

Why the Test is Performed

People with diabetes have an increased risk for kidney damage. The "filters" in the kidneys, called nephrons, slowly thicken and become scarred over time. The nephrons begin to leak certain proteins into the urine. This kidney damage can also start to happen before any diabetes symptoms begin. In the early stages of kidney problems, blood tests that measure kidney function are usually normal.

If you have diabetes, you should have this test each year. The test checks for early signs of kidney problems.

Normal Results

In a person with healthy kidneys, only very small amounts of albumin passes from the blood into urine. There is little or no albumin in the urine sample. Normal albumin levels in the urine are less than 30 milligrams (mg) per gram of creatinine.

Normal value ranges may vary slightly among different laboratories. Some labs use different measurements or may test different specimens. Talk to your provider about the meaning of your test results.

What Abnormal Results Mean

If the test finds a high level of albumin in your urine, your provider may have you repeat the test.

Abnormal results may mean your kidneys are starting to get damaged. But the damage may not yet be bad. If the amount of albumin in the urine is not severe, it is called microalbuminuria.

Abnormal results are most often reported as 30 mg of albumin per gram of creatinine or more.

If you have even more severe kidney damage and there is 300 mg of albumin per gram of creatinine or more, it is called macroalbuminuria.

You will need more tests to confirm a problem and show how severe the kidney damage may be.

If this test shows that you are starting to have a kidney problem, you can get treatment before the problem gets worse. There are a number of medicines that have been shown to slow the progression of kidney damage. Talk to your provider about specific medicines. People with severe kidney damage may need dialysis. They may eventually need a new kidney (kidney transplant).

The most common cause of a high level of albumin in the urine is diabetes. Controlling your blood sugar level may lower the albumin level in your urine.

A high albumin level may also occur with:

• Some immune and inflammatory disorders affecting the kidney
• Some genetic disorders
• Rare cancers
• High blood pressure
• Inflammation in the whole body (systemic)
• Narrowed artery of the kidney
• Fever or exercise

Healthy people may have a higher level of protein in the urine after exercise. People who are dehydrated may also have a higher level.

Risks

There are no risks with providing a urine sample.

References

Brownlee M, Aiello LP, Sun JK, et al. Complications of diabetes mellitus. In: Melmed S, Auchus RJ, Goldfine AB, Koenig RJ, Rosen CJ, eds. Williams Textbook of Endocrinology. 14th ed. Philadelphia, PA: Elsevier; 2020:chap 37.

American Diabetes Association Professional Practice Committee. 11. Chronic kidney disease and risk management: Standards of Care in Diabetes-2024. Diabetes Care. 2024;47(Suppl 1):S219-S230. PMID: 38078574 pubmed.ncbi.nlm.nih.gov/38078574/.

Krishnan A, Levin A. Laboratory assessment of kidney disease: glomerular filtration rate, urinalysis, and proteinuria. In: Yu ASL, Chertow GM, Luyckx VA, Marsden PA, Skorecki K, Taal MW, eds. Brenner and Rector's The Kidney. 11th ed. Philadelphia, PA: Elsevier; 2020:chap 23.

Riley RS, McPherson RA. Basic examination of urine. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 29.