Proteins such as albumin are made in your liver and then circulated in your bloodstream. Albumin is the main protein that circulates in your blood. Your kidneys filter your blood to remove waste products, which are sent to your bladder as urine. Normally, with healthy kidneys, very little protein (including albumin) is lost during this process.
But if blood vessels in your kidneys are damaged, you lose more protein through your urine. If you lose a lot, the protein levels in your blood fall. This can cause health problems because these proteins in your blood regulate the amount of fluid in your body. Without them, fluid builds up in body tissues and makes them swell.
Microalbuminuria means you’re losing more than the normal amount of albumin in your urine per day. It’s a very early stage of protein loss and doesn’t cause protein levels in your blood to drop, so you won’t feel poorly. But it is a marker of things to come and may indicate kidney damage or kidney disease.
Some people are more likely than others to develop microalbuminuria and kidney problems. You’re at particular risk if you have type 1 or type 2 diabetes, high blood pressure, heart disease or another condition that affects your kidneys, like lupus.
If you’ve got microalbuminuria, you probably won’t notice any symptoms. At later stages, when your kidneys aren’t working well, you may see changes in your urine and your skin may get puffy. But the only way to check for microalbuminuria is through a urine test. See our section on diagnosis of microalbuminuria for more information.
If you’ve got diabetes, microalbuminuria may be spotted during routine check-ups. Or your GP may suspect you’re at risk because of your medical and family history. They’ll ask you to provide a urine sample, which will be sent to a laboratory for testing.
There are different types of test but the most reliable way to diagnose microalbuminuria is to check your urine for its albumin to creatinine ratio (ACR). This can spot microalbuminuria early on.
The ACR test measures how well your kidneys are working. It compares the amount of albumin in your urine with the amount of creatinine, a waste product from your muscles. Creatinine is produced and lost (through urine) at a steady rate so measuring it against albumin levels is a good indicator of any problems.
Microalbuminuria is diagnosed when your ACR is 3mg/mmol or higher. This is three times the normal amount.
In the past, you may have been asked to collect urine samples over a 24-hour period, at set times. But now new tests are more accurate, especially if you give a sample first thing in the morning.
You may be asked to provide more than one urine sample. Probably at least twice and a couple of weeks apart, over a six-month period, to confirm the diagnosis. Your ACR can fluctuate (rise and fall) daily, and test results can be affected by a variety of things. This is one of the reasons why you have more than one test. For more information about this, see our FAQ: Microalbuminuria tests.
If you’ve got diabetes, you have a higher risk of microalbuminuria and you’ll be offered an annual test. This is usually from when you’re first diagnosed with type 2 diabetes and from five years after you’ve been diagnosed with type 1 diabetes. You may also be tested for microalbuminuria if you’ve just been diagnosed with high blood pressure.
Your GP may want to refer you to a specialist if your ACR is really high or if you show signs of kidney damage. You specialist will be a diabetic specialist (if you have diabetes) or a nephrologist (a specialist in kidney conditions and treatment). They may want to do additional tests to rule out other conditions.
If you have microalbuminuria, your GP will monitor your condition and may refer you to a nephrologist. This is a doctor who specialises in kidney care and treating kidney diseases. You will usually have a urine test at least once a year after being diagnosed with microalbuminuria.
Treating microalbuminuria with medicines and lifestyle changes can help prevent further damage to your kidneys. It can also reduce the risk of damage to other organs such as your heart.
There are things you can do to stop microalbuminuria getting worse and prevent further damage to your kidneys. Losing excess weight and reducing your blood pressure and cholesterol level will help. Your GP may advise you to:
- exercise regularly, aiming for 150 minutes of moderate intensity activity each week (if you’re able to)
- eat healthily
- stop smoking (including e-cigarettes)
- cut down on alcohol
- monitor and control your blood sugar levels if you have diabetes
Medicines called angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) can help to slow down kidney damage. These medicines can help to reduce your blood pressure. This is important because high blood pressure can speed up the development of kidney disease.
Having microalbuminuria can be a sign of cardiovascular disease, so your GP may prescribe a medicine called a statin. Statins lower your cholesterol, which can reduce the chance of having a heart attack or stroke. Whether or not your doctor prescribes statins may depend on your age and if you've got a condition that makes you more likely to develop heart disease. Your GP may also advise you to take aspirin daily if you're particularly at risk of a heart attack or stroke. For more information, see our FAQ: Microalbuminuria medicines.
It’s still really important to continue with the lifestyle measures because they will give you benefits additional to those of the medicine you’re taking. Your treatment is very much a combined approach and it’s important not to rely solely on your medicine.
Microalbuminuria is a possible complication of type 1 or type 2 diabetes, even if it’s well controlled. Around one in five people develops microalbuminuria within 15 years of being diagnosed with diabetes.
As well as diabetes, other risk factors make you more likely to develop microalbuminuria, especially in combination. These include:
Microalbuminuria is a sign that you’re at particular risk of developing serious and potentially life-threatening conditions like chronic kidney disease and coronary heart disease. That’s why it’s important to diagnose the condition early on.
Long-term complications of chronic kidney disease can include sight and circulation problems and may affect your bones and blood as well as your heart.
About three in four people with diabetes will develop some stage of chronic kidney disease during their life. But it can take years for microalbuminuria to get to the stage where your kidneys fail and you need dialysis or a transplant. This happens in a small number of people with kidney problems. Treatment and lifestyle changes can help slow down and reduce this risk.
And half of people with diabetes who get microalbuminuria won’t go on to develop more serious levels of protein in their urine.
Microalbuminuria is sometimes called ‘incipient nephropathy’ because it can be the start of nephrotic syndrome. This is when there are very high levels of protein in your urine and low levels in your blood because of failing kidneys. It causes swelling, especially around the eyes and in hands and feet.
For more information about the long-term health risks of microalbuminuria, see our FAQ: Long-term health risks.
A healthy diet can slow the progression of microalbuminuria and kidney problems, especially if it also lowers blood pressure and cholesterol, and prevents obesity. In particular it’s important to try to cut down on:
It’s not clear whether strictly limiting the amount of protein you eat makes a difference to how much protein you lose in your urine. But a very low-protein diet is hard to stick 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 further limit your intake of certain foods, such as those containing high levels of protein, sodium, potassium or phosphate. If you need to do this, your specialist (a nephrologist who specialises in kidney conditions) can refer you to a dietitian for advice.
No, one positive test isn't enough to say for certain that you’ve got kidney disease or that your kidneys are damaged. There are other things that can cause albumin to be present in your urine when you give a sample. These include:
- vigorous exercise
- illness (such as a fever)
- a urine infection
- blood in your urine (including periods in women)
- unstable blood sugar levels
- how concentrated your urine is
- how much you’ve had to drink (i.e. not drinking enough water)
- what you’ve been eating (especially high-protein foods like meat)
These may lead to false positive test results that show microalbuminuria even though it’s only temporary. People who have diabetes that isn't well controlled may be more likely to get urine infections. This is because diabetes can affect your body’s immune system, making it harder to fight infection. 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 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’s some damage to your kidneys, you can get the right treatment quickly.
Your GP may recommend that you take medicines called angiotensin converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs). These are often prescribed to help lower blood pressure and can also stop microalbuminuria getting worse.
ACE inhibitors work by preventing a particular hormone from being released in your body. This 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 may 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.
Microalbuminuria can be a sign of cardiovascular disease. So, if you have other cardiovascular risk factors such as high blood pressure or diabetes, your GP may prescribe a cholesterol-lowering medicine called a statin. You may also be asked to take aspirin daily if you have blood clotting problems, especially if you’ve already had a heart attack or stroke.
Your doctor may refer you to a specialist if your blood pressure is still too high after trying several different medicines.
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.
You should also talk to your doctor about other medicines you take, such as diuretics and painkillers. They may make kidney damage worse or stay in your system because your microalbuminuria means you get rid of less waste in your urine.
If you have microalbuminuria, it doesn't always mean that you have kidney disease or that you’ll 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 successfully treated and for a few people, it can even be reversed.
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. This is particularly so if your diabetes isn't well controlled, if 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. Once this has developed, it means there is 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 healthy eating and benefits of exercise.
Try to limit sedentary activity (like sitting). Aim to exercise several times a week, even if it's just a brisk walk at lunchtime. Eat carbohydrates that release energy slowly, such as porridge oats, brown rice and beans, with every meal and snack. And don’t forget your five portions of fruit and veg every day.
If you’re pregnant and have diabetes, you’ll have a check on how your kidneys are working early in your pregnancy. You may be referred to a nephrologist, who specialises in kidney problems, if your ACR is high. Your blood pressure will also be carefully monitored and managed.
The usual medicines for treating microalbuminuria and high blood pressure aren’t suitable for pregnant women. Your doctor may suggest alternatives and medicines to thin your blood and stop it clotting if your ACR is particularly high.
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Reviewed by Natalie Heaton, Specialist Health Editor, Bupa Health Content Team, June 2017
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