Microalbuminuria

About microalbuminuria

Your blood contains cells and proteins that your body requires, as well as waste products that it needs to get rid of. Your blood is filtered by your kidneys, and waste products are removed from your body in your urine. Usually, cells and proteins 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 is 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 involved in filtering waste products in your kidneys are damaged and your kidneys begin to lose their ability to filter proteins out of your urine.

Microalbuminuria is defined as losing 30 to 300 milligrams of albumin in your urine per day. If you lose more than this, you may have a condition called proteinuria, which is when the levels of protein in your urine are higher than 300 milligrams per day.

Microalbuminuria can often be the first sign of kidney damage or kidney disease. People with type 1 and type 2 diabetes may develop kidney damage as a complication of their 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.

Symptoms of microalbuminuria

If you have microalbuminuria, you won’t have any symptoms. The only way you will know if you have microalbuminuria is to have a test. See our diagnosis of microalbuminuria section for more information.

Causes of microalbuminuria

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: 

  • high blood pressure
  • a family history of diabetic kidney disease
  • smoking
  • being overweight

Diagnosis of microalbuminuria

If your GP thinks you may be at risk of having microalbuminuria, he or she may ask you to do a urine test. He or she may also ask about your medical history.

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:

  • 2.5mg/mmol or higher (for men)
  • 3.5mg/mmol or higher (for women)

If your GP thinks you have microalbuminuria, you may be asked to collect more than one urine sample on several occasions to confirm the diagnosis.

Your GP may ask you to collect all of your urine over a set amount of time (such as over four hours, overnight, or even over a 24-hour period). This is because the 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 your urine 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 30 to 300 milligrams of albumin in your urine, you will be diagnosed with microalbuminuria. However, the test results can be affected by:

  • recent exercise (within 24 hours before the test)
  • illness
  • a urine infection
  • periods or pregnancy in women
  • high blood pressure
  • uncontrolled blood sugar levels

Tell your GP or nurse if you have any health problems or if any of the other factors above apply to you. If you have exercised within a day of being due to start collecting your urine, the test can be rearranged for another day.

Treatment of microalbuminuria

If you have microalbuminuria, your GP will monitor your condition and may refer you to a specialist. You will usually be asked to have a urine test at least once a year and your doctor will discuss the different types of treatment available.

Self-help

Diet and exercise play a key role in controlling your blood sugar levels and reducing your weight, blood pressure and cholesterol level – in turn preventing any further kidney damage. Your GP may advise you to:

  • exercise regularly, aiming for 150 minutes of moderate intensity activity each week
  • eat at least five portions of fruit and vegetables a day
  • choose to eat carbohydrates that release energy slowly, such as porridge oats, brown rice and pasta, lentils and beans and not to eat those that release energy quickly, such as white bread and white rice
  • reduce the amount of sugar, fat and salt in your diet
  • stop smoking
  • cut down on alcohol
  • monitor and control your blood sugar levels if you have diabetes

If you develop kidney disease, you may need to change your diet to prevent a build-up of waste products in your kidneys 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

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, or if you're younger and have other cardiovascular risk factors, such as high blood pressure or diabetes. Your GP may advise you to take 75 milligrams of aspirin daily if you're particularly at risk of heart attack or stroke, especially if you've already had one or the other in the past. See our common questions for more information.

Is just one positive test for microalbuminuria enough to diagnose kidney problems?

Answer

No, one positive test isn't enough to say for certain that you have kidney problems. If you have one positive test, your GP will arrange for you to have further tests. Don't ignore a positive result – make sure you get tested again. If further tests show there is some damage to your kidneys, you can get the right treatment quickly. 

Explanation

A single positive test for microalbuminuria doesn't always mean that you have kidney disease or that your kidneys are damaged. These are some other things that can cause albumin to be present in your urine, including:

  • recent exercise (within 24 hours of the test)
  • illness
  • a urine infection
  • periods or pregnancy in women
  • high blood pressure
  • uncontrolled blood sugar levels

People who have diabetes that isn't well controlled may be more likely to get urine infections because diabetes can affect your body’s immune system, making it harder to fight infections. Without treatment, a urine infection can damage your kidneys, so always see your GP if you think you have an infection.

If you have one positive urine test that shows microalbuminuria, your GP will usually ask you to have the test repeated. The results of these further tests will help your GP to decide what type of treatment you need.

I have diabetes and microalbuminuria. My GP has told me I might need to take medicines to treat it. What will these be?

Answer

Your GP may recommend that you take medicines to treat microalbuminuria. In order to protect your kidneys, you can take medicines called ACE inhibitors and ARBs. Controlling your blood sugar levels and your blood pressure can also help to protect your kidneys and slow down any damage to them. 

Explanation

ACE inhibitors and ARBs are medicines that people with high blood pressure often take to help lower their blood pressure levels. ACE inhibitors work by preventing a hormone from being released in your body, which helps to widen your blood vessels and lower your blood pressure. ARBs work in a similar way. They are given to people who can't take an ACE inhibitor, for example, those people who get side-effects.

ACE inhibitors can prevent further damage to your kidneys and can, in some people, reverse any kidney damage. So, some people can go from having a small amount of albumin in their urine to no albumin at all. ACE inhibitors may also have the added benefit of protecting your heart and circulation. Because of this, your doctor may advise you to take an ACE inhibitor even if you don't have high blood pressure.

The most common side-effects of ACE inhibitors are:

  • a dry, irritating cough that won't go away
  • a drop in blood pressure when you first take them – this can make you feel dizzy or faint

ARBs are an alternative to ACE inhibitors. They also have side-effects including feeling sick and tiredness. Always ask your GP for advice and read the patient information leaflet that comes with your medicine. If you think you're having side-effects from your medicines, speak to your GP.

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, or if you're younger and have other cardiovascular risk factors, such as high blood pressure or diabetes. You may also be asked to take 75mg of aspirin daily if you have blood clotting problems, especially if you have already had a heart attack or stroke.

If I have microalbuminuria, will I develop kidney disease or kidney failure?

Answer 

If you have microalbuminuria, it doesn't always mean that you have kidney disease or that you will develop kidney failure. But don't ignore a positive test for microalbuminuria and make sure you start any treatment you need straightaway. Microalbuminuria can be effectively treated and for a few people it can even be reversed. 

Explanation

Microalbuminuria is often linked to two conditions – diabetes and high blood pressure. If you have either of these conditions or both together, you're more likely to develop kidney problems, particularly if your diabetes isn't well controlled, you have a raised cholesterol level or if you smoke.

It's important to have regular checks for albumin in your urine if you have diabetes, high blood pressure, or both. If it isn't treated, microalbuminuria will get worse and the amount of protein in your urine will increase. A large amount of protein in your urine is called proteinuria and once this has developed, it means there will be permanent damage to your kidneys that can't be reversed.

If you have diabetes and microalbuminuria, you're at a higher risk of developing heart disease or having a stroke in the future. So, it makes good sense to look after your health and follow your treatment to prevent microalbuminuria from getting worse. This means taking medicines if you need to, controlling your blood sugar levels and lowering your blood pressure and cholesterol level through diet and exercise.

Try to exercise for 150 minutes each week, even if it's just a brisk walk at lunchtime. Eat five portions of fruit and vegetables a day and carbohydrates that release energy slowly, such as porridge oats, brown rice and beans, with every meal and snack.