Proteinuria means there is an abnormal amount of protein in the urine (wee). Normally there is very little protein that is lost in the urine.

Many children with proteinuria have no symptoms. Although all children who have proteinuria need tests, in many it goes away without treatment.

In a few children, the proteinuria is a sign of a problem with the kidneys, and they may need special treatment. Some children lose a lot of protein, which can cause the body to swell – this is called nephrotic syndrome.

About proteinuria

Proteinuria means there is more protein than normal in the urine. It happens when the kidneys leak protein into the urine. Protein is an important part of our diet and is in most foods.

There are different types of proteins in the blood. The most common type is called albumin.

Often, only albumin is found in the urine – this is called albuminuria. If there is only a very small amount of albumin in the urine, this is called microalbuminuria.

How common is proteinuria?

Doctors have found proteinuria in about 2 or 3 out of 100 children of any age. In most children this is mild proteinuria that is harmless.

Almost 1 in 100 children have persistent proteinuria, which means that it continues over time. This may be more serious.

Symptoms of proteinuria

Most children with proteinuria do not have any symptoms. You cannot usually see protein in the urine, but occasionally the urine looks frothy.

Nephrotic syndrome

When the kidneys leak a lot of protein this is called nephrotic range proteinuria. This causes nephrotic syndrome.

Children often have swelling in their body, especially their face, legs and feet. 


Haematuria means there is blood in the urine. If there is a lot, the urine may be red or dark brown. This is occasionally seen with proteinuria.

Causes of proteinuria

Some children have protein in their urine only at certain times of the day, after exercise, or during a fever or a urinary tract infection when germs get into the urine and travel up the urinary system. In these cases, it is not serious.

A small number of children have large amounts of protein in the urine, or have persistent proteinuria. This may happen:

Proteinuria tests and diagnosis 

Your child’s doctor can diagnose (identify) proteinuria with a urine test. Proteinuria may be found during a urine test for another reason – for example, if your doctor thinks your child has another condition or during a routine health check. Your doctor will also speak with you and your child about his or her symptoms and examine your child.

If the first test shows there is protein in your child’s urine, he or she will need more tests to help find out whether the proteinuria is serious. Your child may need further tests, such as blood tests.

Treatment for proteinuria

Many children will not need treatment. Some children will need to be monitored or treated, and may need to take medicines to reduce the amount of protein lost in their urine or control their blood pressure.

About the future

For many children, proteinuria is mild and will go away in a few weeks without any treatment.

In a few children, proteinuria is a sign of kidney damage – for example, scars or inflammation. Often this damage is minor and their kidneys work normally. They may need to go back to hospital or clinic for occasional follow-up appointments.

A very small number of children will have long-term problems with their kidneys. These children may need further care. They will need to go back to the hospital or clinic for regular follow-up appointments.

More information

  • Urinary tract infection (UTI)

    Urinary tract infections happen when germs get into the urine (wee) and travel into the urinary tract.

  • Haematuria

    Haematuria means there is blood in the urine (wee). Normally there is no blood in the urine. Your child's doctor will try to find out what is causing this.

  • Nephrotic syndrome

    Nephrotic syndrome happens in children whose kidneys leak too much protein into their urine, and causes swelling in the body.