Microalbuminuria is when between 30 and 300mg (milligrams) of a protein called albumin pass through your kidneys and into your urine. This can be a sign of underlying conditions, such as kidney disease or cardiovascular disease.
Your blood contains cells and proteins that your body needs, as well as waste products that you have to get rid of. Your blood is filtered by your kidneys and the waste products are removed from your body in your urine. Cells and proteins usually stay in your blood, but sometimes a small amount of protein is lost into your urine along with other waste products.
Albumin is a protein that’s produced in your liver. If your kidneys are working properly, very little albumin will be lost in your urine. However, if you have microalbuminuria, the blood vessels that filter waste products in your kidneys are damaged. This means your kidneys begin to lose their ability to filter proteins out of your urine.
Microalbuminuria is defined as losing between 30 and 300mg of albumin in your urine per day. If you lose more than this, you may have a condition called proteinuria.
Microalbuminuria can often be the first sign of kidney damage or kidney disease. If you have type 1 or type 2 diabetes, you may develop kidney damage as a complication of your diabetes. If you have diabetes and microalbuminuria is detected early, there are treatments that may slow down any further damage to your kidneys.
Microalbuminuria can also be a sign of more widespread damage to your blood vessels, including those of your heart. Microalbuminuria can be a sign that you're at an increased risk of heart disease, particularly if you have type 2 diabetes.
If you have microalbuminuria, you won’t have any symptoms. The only way you will know if you have microalbuminuria is to have a urine test. See our diagnosis of microalbuminuria section for more information.
Microalbuminuria is a possible complication of type 1 or type 2 diabetes. As well as diabetes, there are several other risk factors that make you more likely to develop microalbuminuria. These include:
If your GP thinks you’re at risk of microalbuminuria, they may ask you to do a urine test. Your urine sample will usually be sent to a laboratory for testing. There are several ways to diagnose microalbuminuria.
Your urine may be tested for its albumin to creatinine ratio. This measures how well your kidneys are working. You may be diagnosed as having microalbuminuria if your albumin to creatinine ratio is higher than:
If your GP thinks you have microalbuminuria, you may be asked to provide more than one urine sample on several occasions to confirm the diagnosis.
Your GP may ask you to collect urine samples over a set amount of time (such as over four hours, overnight or over a 24-hour period). This is because levels of protein can vary throughout the day and night so it will help to give a more accurate measurement of how much albumin you lose in your urine. If you’re asked to collect urine samples over a set amount of time, it will be tested for its level of albumin instead of its albumin to creatinine ratio. If you have between 30 and 300mg of albumin in your urine, you’ll be diagnosed with microalbuminuria. However, the test results can be affected by:
Tell your GP or nurse if you have any health problems or if any of the above factors apply to you. Your urine test can be rearranged for another day.
If you have microalbuminuria, your GP will monitor your condition and may refer you to a specialist. Your specialist will discuss the different types of treatment available. You will usually have a urine test at least once a year after being diagnosed with microalbuminuria.
To prevent further damage to your kidneys, it’s important to control your blood sugar levels. Losing excess weight and reducing your blood pressure and cholesterol level will help. Your GP may advise you to:
If you develop kidney disease, you may need to change your diet to prevent a build-up of waste products and prevent further kidney damage. You may need to limit the amount of certain foods you eat, such as those that contain high levels of protein, sodium, potassium or phosphate. If you need to do this, your GP can refer you to a dietitian for advice.
Medicines called angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) can help to slow down kidney damage. These medicines can also help to reduce your blood pressure.
Having microalbuminuria can be a sign of cardiovascular disease, so your GP may prescribe a cholesterol-lowering medicine called a statin if you're over 40. They may also prescribe a statin if you're younger and have other cardiovascular risk factors, such as high blood pressure or diabetes. Your GP may advise you to take 75mg of aspirin daily if you're particularly at risk of a heart attack or stroke. See our frequently asked questions for more information.
Reviewed by Dylan Merkett, Bupa Health Information Team, August 2014.
For answers to frequently asked questions on this topic, see FAQs.
For sources and links to further information, see Resources.
This information was published by Bupa's Health Information Team and is based on reputable sources of medical evidence. It has been reviewed by appropriate medical or clinical professionals. Photos are only for illustrative purposes and do not reflect every presentation of a condition. The content is intended only for general information and does not replace the need for personal advice from a qualified health professional. For more details on how we produce our content and its sources, visit the about our health information page.
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