What is a microalbumin creatinine ratio test?

A microalbumin creatinine ratio urine test checks the levels of the protein albumin in your urine (pee). Abnormal amounts of this protein may be an early sign of kidney disease.

Your kidneys are two organs on either side of your spine near your waist. Filters in your kidneys remove waste and extra water from your blood and gets rid of them through urine. Albumin, however, is not a waste product. It is a common protein found in blood. Therefore, very little, if any, of it should pass into your urine.

In healthy kidneys, only a trace of albumin, at most, will get through the filters. This trace is often called microalbumin. But if your kidneys are damaged, large amounts of albumin may pass into your urine.

Creatinine, however, often appears in your urine. It is a waste product that comes from daily wear and tear on your muscles. Your kidneys usually get rid of this protein at a steady rate. The microalbumin creatinine ratio test compares the levels of albumin in your urine to your levels of creatinine. This ratio can help your health care provider tell if your body is getting rid of albumin at an increased rate.

Other names: albumin-creatinine ratio; urine albumin; microalbumin, urine; ACR; UACR

What is it used for?

A microalbumin creatinine ratio test is most often used to look for signs of kidney disease in people who have a high risk of developing it but don't have symptoms. You're more likely to develop kidney disease if you:

• Have diabetes
• Have high blood pressure
• Have a family health history of kidney disease, diabetes, or high blood pressure
• Have heart disease
• Are over 50 years old
• Smoke
• Have obesity

A microalbumin creatinine ratio test may be used to monitor your kidneys if you have been diagnosed with kidney disease. It can also help your provider see how well any treatment for kidney disease is working.

Why do I need a microalbumin creatinine ratio test?

Early kidney disease usually doesn't have any symptoms. So, if you have a high risk for kidney disease, you need a microalbumin creatinine ratio test so you can determine if you have early signs of kidney disease. If you do, treating it early can keep it from getting worse.

Because diabetes is the most common causes of kidney disease, it is important for anyone with this condition to get tested for kidney disease every year.

If you have other conditions that increase your risk for getting kidney disease, such as high blood pressure or heart disease, ask your provider how often you need to get tested.

What happens during a microalbumin creatinine ratio test?

There are several ways to collect a urine sample for a microalbumin creatinine ratio test:

• A "random" or "spot" urine sample means that you collect a single urine sample at any time of the day. You will usually collect this sample at your provider's office or at a medical lab.
• An early morning or timed urine sample is collected first thing in the morning or after not going to the bathroom for four hours. You'll likely be given a kit and instructions on how to collect your urine at home.
• A 24-hour urine sample requires you to collect all your urine over a 24-hour period. This test is usually used to follow up on abnormal results from a test on a single sample of urine. A 24-hour urine test is the most accurate way to measure albumin in urine.

For a random urine sample, a health care professional may give you a cleansing wipe, a small container, and instructions for how to use the "clean catch" method to collect your urine sample. It's important to follow these instructions so that germs from your skin don't get into the sample:

1. Wash your hands with soap and water and dry them.
2. Open the container without touching the inside.
3. Clean your genital area with the cleansing wipe:
   • For a penis, wipe the entire head (end) of the penis. If you have a foreskin, pull it back first.
   • For a vagina, separate the labia (the folds of skin around the vagina) and wipe the inner sides from front to back.
4. Urinate into the toilet for a few seconds and then stop the flow. Start urinating again, this time into the container. Don't let the container touch your body.
5. Collect at least an ounce or two of urine into the container. The container should have markings to show how much urine is needed.
6. Finish urinating into the toilet.
7. Put the cap on the container and return it as instructed.

For home collection for an early morning or timed urine sample, the instructions will be about the same as for a random urine sample. Be sure to follow the instructions that come with your collection kit.

For a 24-hour urine sample, you'll be given a special container to collect your urine over a full day and instructions on how to collect and store your sample. Your provider will tell you what time to start. The test generally includes the following steps:

• To begin, urinate in the toilet as usual. Do not collect this urine. Write down the time you urinated.
• For the next 24 hours, collect all your urine in the container.
• During the collection period, store the urine container in a refrigerator or in a cooler with ice.
• 24 hours after starting the test, try to urinate if you can. This is the last urine collection for the test.
• Return the container with your urine to your provider's office or the laboratory as instructed.

If you have hemorrhoids that bleed or are having your menstrual period, tell your provider before your test.

Will I need to do anything to prepare for the test?

Before providing your urine sample, you may need to avoid:

• Intense exercise. Hard exercise may increase the amount of albumin in your urine for a short time.
• Eating meat. Meat can affect your creatine levels, so you may be asked not to eat any for a day before your test.

Check with your provider about how to prepare for your test. Be sure to ask if any medicines or supplements you take could affect your results.

Are there any risks to the test?

There is no known risk to providing a urine sample for a microalbumin creatinine ratio test.

What do the results mean?

If your microalbumin creatinine ratio shows an abnormal amount of albumin in your urine, you will likely need more tests to confirm your results. That's because temporary increases in albumin levels may be caused by exercise, certain medicines, fever, and inflammation in the body.

Usually, you will have two more tests during the three to six months after your first test. If two out of three tests show abnormal levels of albumin in your urine, you may have early-stage kidney disease.

Higher or increasing amounts of albumin in your urine usually mean you have:

• More serious kidney disease that's likely to get worse faster.
• A higher risk for developing problems with your heart and blood vessels (vascular diseases).

If you have higher-than-normal amounts of albumin in your urine, you may need to be tested more often.

Smaller amounts of albumin in your urine don't always mean you have kidney disease. Other conditions that cause inflammation may increase albumin in urine, including:

• Urinary tract infections.
• Gum infections (periodontitis).
• Hepatitis.

Your test results may also be affected by your muscle density and your diet, age, and race.

If you have an abnormal result, your provider will usually order other kidney tests, including a blood test called an estimated glomerular filtration rate (eGFR) test. Talk with your provider about what your test results mean. If you're diagnosed with early kidney disease, there are steps you can take to reduce the amount of albumin in your urine and protect your health.

Learn more about laboratory tests, reference ranges, and understanding results.

Is there anything else I need to know about a microalbumin creatinine ratio?

It's easy to confuse prealbumin with albumin. Although they sound similar, prealbumin is a different type of protein. A prealbumin test is not part of testing your kidney health.