What to Know About a Microalbuminuria Test

A microalbuminuria test gauges the quantity of a protein called albumin detected in your urine and serves as a way to assess how well your kidneys are functioning. It is also referred to as an albumin-to-creatinine ratio (ACR) test or a urine albumin examination.

If your clinician suspects you might be at risk for kidney injury or disease, you’re likely to undergo or have already undergone a microalbuminuria test. This urine test determines the level of albumin in your urine.

Albumin is a protein that your body utilizes for cell growth and tissue repair. It normally circulates in the bloodstream. A certain concentration of it in your urine can indicate kidney damage.

Your kidneys handle waste removal from the blood and regulate your body’s water balance. Healthy kidneys ensure waste is filtered out and essential nutrients and proteins, such as albumin, remain in your system.

Ensuring your kidneys function properly is crucial so that albumin stays in your blood. If kidney damage occurs, they may fail to retain albumin, causing it to spill into your urine. When this happens, you may develop a condition known as albuminuria. Albuminuria simply means that your urine contains albumin.

The microalbuminuria test is also known as the albumin-to-creatinine ratio (ACR) test or the urine albumin test.

What is the goal of the test?

Your clinician may suggest a microalbuminuria test if you’re at risk for kidney injury or if they suspect your kidneys could be damaged. Early detection is important because treatment may slow or prevent progression to kidney disease. The two most common causes of kidney disease in the United States are diabetes and hypertension (high blood pressure). Your clinician may order the microalbuminuria test if you have one of these conditions.

The aim of the microalbuminuria test is to quantify the amount of albumin present in the urine. The test is typically paired with a creatinine test to provide an albumin-to-creatinine ratio. Creatinine is a waste product filtered out by the kidneys. When kidney damage occurs, urinary creatinine levels drop while albumin levels may rise.

How frequently you need microalbuminuria tests depends on whether you have underlying conditions or symptoms of kidney damage. Early kidney damage often presents no noticeable signs. However, if damage is extensive, your urine may appear foamy. You may also experience swelling, or edema, in your:

• hands
• feet
• abdomen
• face

Diabetes

It is advised that individuals with diabetes undergo an annual microalbuminuria test. Diabetes can harm the kidneys, and a microalbuminuria test can detect this damage.

If you have positive results and you have diabetes, your clinician should confirm the results with additional testing over a three- to six-month period. If kidney damage is confirmed, your clinician will be able to treat the injury and help improve and preserve kidney function.

High blood pressure

If you have hypertension, your clinician may also screen you for kidney damage using the microalbuminuria test. High blood pressure can damage the kidney vessels, leading to albumin leaking into the urine. Regular albumin testing should be performed. Your clinician will decide when you need this test.

Preparation for the test

The microalbuminuria test is a straightforward urine test. You can eat and drink normally beforehand. No special preparation is required.

How is the test performed?

Several types of microalbuminuria urine assessments are available:

Random urine test

You can perform a random urine test at any time. Clinicians often combine it with a creatinine test to enhance result accuracy. This test can be done in any healthcare setting. You’ll collect the sample in a sterile cup, and your clinician will send it to a laboratory for analysis.

24-hour urine test

For this test, you must collect all of your urine for a 24-hour span. Your clinician will supply a container for urine collection that must be kept refrigerated. After collecting for 24 hours, return the sample to your healthcare provider for laboratory analysis.

Timed urine test

Your clinician may request a urine sample first thing in the morning or after a four-hour interval without urination.

Once the laboratory reports the results, your clinician can provide more information about what they mean.

What are the risks of the test?

The microalbuminuria test only requires normal urination. This procedure carries no risks, and you should not experience any discomfort.

Interpreting your results

According to the National Kidney Foundation, albuminuria denotes excessive albumin in the urine. Microalbuminuria indicates a mildly elevated level of protein in the urine, while macroalbuminuria refers to a very high level of albumin in the daily urine. Microalbuminuria results are expressed in milligrams (mg) of protein leakage per 24 hours. Typically, results are interpreted as follows:

• Less than 30 mg of protein is considered normal.
• Thirty to 300 mg of protein is termed microalbuminuria and may signal early kidney disease.
• More than 300 mg of protein is known as macroalbuminuria and points to more advanced kidney disease.

Several temporary factors can cause higher-than-normal urinary microalbumin results, such as:

• blood in the urine, or hematuria
• fever
• recent intense exercise
• dehydration
• a urinary tract infection

Certain medications can also affect albumin levels in the urine. Examples include:

• acetazolamide (Diamox Sequels)
• antibiotics, including aminoglycosides, cephalosporins, penicillin, polymyxin B, and sulfonamides
• antifungal medications, including amphotericin B (Abelcet) and griseofulvin (Gris-PEG)
• lithium, used to treat bipolar disorder
• nonsteroidal anti-inflammatory drugs (NSAIDs) like aspirin (Bufferin), ibuprofen (Advil), and naproxen (Aleve)
• penicillamine (Cuprimine), previously used for rheumatoid arthritis
• phenazopyridine (Pyridium), used to treat urinary tract pain
• tolbutamide, used to treat diabetes

After processing your results, your clinician may request a re-test if the initial results are abnormal. If needed, they will discuss the best treatment options for your kidney damage and its underlying cause.

Measuring how much albumin is present in your urine is essential for detecting kidney damage. Kidney damage can progress to kidney disease or failure. Should kidney failure occur, dialysis is often required. By identifying kidney damage early, your clinician can slow further progression and help maintain kidney function over the long term.