Urine that is red or reddish-brown may contain blood. The urine can also be red-colored by things that the child has eaten, such as beets or some medicines. The most common cause of blood in the urine of children is urinary tract infection. If the child has a urinary tract infection, they are treated with antibiotics.

Symptoms of blood in the urine of children

The urine is usually yellow, lighter or darker depending on how much the child has been drinking. If the urine is red or reddish-brown it may contain blood.

Sometimes it does not appear if the child has blood in the urine. Then it can be detected if the child leaves a urine sample for some other reason.

Newborn babies may have a brick-red spot in the diaper for the first few days of their lives. It is usually not blood but depends on salts in the urine, so-called urate crystals. It is harmless and goes away after a few days.

When and where should I seek care?

If you think your child has blood in the urine, contact a health care center, pediatric emergency room or on-call clinic. If closed, you can wait until the on-call reception or medical center opens.

If a child has blood in the urine and at the same time have any of the following symptoms:

  • fever
  • stomach ache
  • back hurts.

If it is closed at the medical center, pediatrician or on-call reception, seek care at an emergency room.


To find out if the child has blood in the urine and what it may be due to, the child is examined in several ways. Here are some examples:

Tell your doctor if more in your family or family have blood in your urine

It is important that you tell your doctor if there are more people in your family or family who have or have had blood in your urine. Sometimes parents, siblings and other relatives also need to be examined. This is because some kidney diseases are hereditary.

Urine sample

To find out if the child has blood in the urine, they may have a urine sample. The urine test can show if there is blood, protein, white blood cells or bacteria in the urine. The urine sample is usually examined first with the urinary tract. When the specimen is examined with a urethra, the stick is first dipped in the urine then the doctor can look at the stick in a microscope.

The urine sample is sent to culture if the doctor thinks the child may have a urinary tract infection. The culture can show what type of bacteria, the number of bacteria and which antibiotics the bacterium is sensitive to.

The child may also be allowed to submit more urine samples. It may be, for example, if the doctor thinks the child has kidney stones or too much calcium in the urine. Then various types of salt in the urine, especially lime, are investigated.

Different ways of passing urine samples

Children who can pee on a request will pee in a container. Instead, children who cannot urinate to urinate receive a special bag around the penis or pubic lips into which the urine can be collected. In babies who have a fever, the urine sample is taken directly from the bladder. It’s called a blue dot. Then a thin needle was inserted through the skin and further into the bladder. The sting is harmless and feels much like taking a blood sample from a blood vessel.


The kidneys can be examined with so-called scintigraphy. Then a particular fluid is injected directly into the blood through a  venous catheter. A vein catheter is a small thin plastic tube that is inserted into a blood vessel by means of a needle which is then removed. The fluid injected gets stuck in the parts of the kidney that work properly. With the help of a special camera, a gamma camera, the doctor can see the areas that are not working or that are affected by an infection.

The examination takes about half an hour and the child must lie on his stomach at all times. Some children need sedative medicine. A relative may be present at all times.

Cystography – MUCG

An examination with the x-ray of the bladder, the urethra, and the ureter can show if the child has changed in the urinary tract that can lead to an increased risk of urinary tract infection. For example, it may be reflux. This means that the urine returns from the bladder to the ureter and kidney. This study is also called cystography.

First, the child gets contrast media through a  catheter in the urethra. Contrast is a fluid that makes urinary and renal pelvis more visible on X-rays. The drug is not absorbed into the body and is not harmful. A catheter is a thin, soft tube that empties the bladder on urine.

The X-ray machine takes pictures partly when the bladder is filled, and partly when the child pours out the contrast medium and the bladder compresses. 

Before the examination, the child usually needs sedative medication.

Blood tests and blood pressure

The child is also often allowed to have a blood test. It can be, for example, to measure blood value, white blood cells, infection value called CRP and how the kidneys work.

The kidneys are the organs that purify the blood from various residual products. By measuring the levels of certain substances in the blood, such as urea and creatinine, the doctor can see how the kidneys work.

In all children with blood in the urine, blood pressure is also checked.

Specimens from the tonsils or from an infected wound

If the child has throat flux or an infected wound, a culture is taken from there. Then a small cotton-covered stick is used, which is ironed against the tonsils or against the wound. The test shows if there are bacteria in it that may have caused kidney inflammation.

Computer tomography of the abdomen

Sometimes a computed tomography of the abdomen is also done. It can show if the child has a kidney injury, such as bleeding after a stroke or an accident.


The child is examined with an x-ray of the stomach if the doctor believes the child has kidney stones. Read more about x-rays of the stomach on children, abdominal overview here.


An ultrasound examination shows the size of the kidneys and how they look. Often, the bladder is also examined at the same time.

Renal function examination – iohexol clearance

During a kidney function examination, the child is first allowed to drink to become piss-needy and then to urinate so that the bladder becomes empty. Then a certain substance is injected into the blood. To inject the substance for a nurse, insert a needle with a thin plastic tube into a blood vessel, a so-called venous catheter. It is usually placed on the top of the hand or in the arms fold. When the plastic hose is in place, the needle is removed and the hose is attached with a bandage.

The study measures how well the kidneys can purify the blood from the injected substance. The survey usually takes a few hours when the measurements are made at intervals. A relative may be present at all times.

kidney Biopsy

The doctor does a kidney biopsy if they suspect the child has a kidney inflammation. Then a sample is taken from the kidney tissue. The child lies down on the stomach or on the side. The doctor begins by examining the kidneys of the child using ultrasound. The images from the ultrasound are transferred to a screen where the doctor can review the results.

Then the doctor puts a thin needle against one kidney. When the needle is pulled out, a very small part of the kidney follows. It’s called a tissue test.

The sample is then analyzed in a laboratory with a microscope.   

Some children are anesthetized during the examination and others receive local anesthetic and sedative drugs. The sampling itself takes a few seconds and the entire examination is completed after about 15 to 30 minutes. A relative may be present at all times. 

There may be a small risk of kidney bleeding after the examination and therefore the child needs to lie down for the nearest 24 hours. They, therefore, need to remain in the hospital on the day the biopsy is done and the day after.

Children should not exercise for the next one to two weeks after the examination.

What does blood in the urine depend on?

Blood in the urine can be due to several different things. The most common cause is urinary tract infection. In the event of a urinary tract infection, bacteria have entered the urethra and then up to the bladder.

Urinary tract infection in boys or bladder infection may be due to certain types of viruses. Then quite a lot of blood can leak from the tiny blood vessels of the irritated mucosa and accompany the urine out. These infections usually resolve within a few days. They are harmless and do not need to be treated with antibiotics.

Blood in the urine may also be due to another form of urinary tract infection called renal pelvic infection. Then the bacteria have spread to one or both kidneys.

Renal inflammation more uncommon cause

A more common cause of blood in the urine of children is renal inflammation, also called glomerulonephritis. Then the child has an inflammation in the part of the kidney which, among other things, cleanses the blood.

Other unusual causes of blood in the urine of children are hereditary kidney disease, kidney stones or limestone crystals that do not form kidney stones. There may also be blood in the urine if the child has fallen or struck in the lower back.

The urine can be red without blood

The urine can be colored red if, for example, the child has eaten beets. Some dyes in candy and some drugs can also color the urine red.

Treatment of blood in the urine of children

The treatment of blood in the urine the child receives depends on the cause of the blood in the urine. Sometimes no treatment is needed.

If the child has a urinary tract infection, they will receive antibiotics. Blood in the urine always disappears when the urinary tract infection is treated.

Small children with renal pelvic infection may need hospital care. Then antibiotics can get directly into the bloodstream.

Kidney stones are treated with shock wave treatment, called ESVL. Then the kidney stone is crushed and the child is then allowed to urinate the parts. It is a urologist who does the treatment.

Renal inflammation associated with bacteria on the tonsils usually does not need to be treated. Other kidney inflammation is assessed by the physician using a renal biopsy.

The child is treated with cortisone if the blood in the urine is due to impaired renal function, high blood pressure or protein in the urine.

Sometimes the doctor cannot find the reason why the child has blood in the urine. Then the doctor follows up on how the baby is feeling for a few years. 

What happens in the body?

The kidneys are important for the body to purify the blood and get rid of substances that are not needed. These substances are called residues. The kidneys also regulate how much fluid needs to be in the bloodstream. The residues and water leave the body with the urine. The urine is formed in the kidneys and is transported through the ureters, collected in the bladder and then continued out through the urethra.

Ehtisham Nadeem

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