Seeing red or brown urine in the potty or nappy is alarming for any parent. In children, the causes are usually different from those in adults, and serious ones are uncommon. This guide explains the two kinds of blood in urine, what can mimic it, the usual causes in childhood, which tests doctors use, and the signs that mean your child needs to be seen quickly.
Visible blood or blood found only on a test
Doctors separate blood in urine (haematuria) into two kinds. In visible haematuria the urine looks pink, red, brown or cola-coloured. NHS paediatric guidance in Scotland notes that as little as 1 mL of blood in a litre of urine can change its colour. In microscopic haematuria the urine looks normal and the blood is found only on a dipstick or under a microscope.
Microscopic blood is common and is often harmless. HealthyChildren.org, from the American Academy of Pediatrics, says many healthy children have it and that it often clears within a few weeks. The same Scottish guidance reports that about 1% of school-aged children have two or more positive dipstick tests, and that the blood is still present six months later in about a third of them. For the adult picture, see our general guide to blood in urine.
Red urine that is not blood
Before any tests, it helps to know that red urine is not always blood. According to the Scottish NHS guidance, beetroot, food colourings, some berries and some medicines can colour urine red or brown. In young babies, concentrated urine can leave orange or pink urate crystals in the nappy. Blood can also come from sore skin around the opening of the urethra, from nappy rash or from the bottom, and then mix with urine.
HealthyChildren.org points out that dipsticks can give wrong results, so a positive result is confirmed under a microscope.
Common causes of blood in urine in children
The causes in children are different from those in adults. Cancer, a key concern in older adults, is very rare in children, according to HealthyChildren.org. The table below lists causes named by HealthyChildren.org and a 2024 review in Child Kidney Diseases, with clues parents may notice.
| Cause | Clues parents may notice |
|---|---|
| Urine infection | Fever, pain or stinging when passing urine, going often. See urine infection in children. |
| High calcium in the urine (hypercalciuria) | Often no other symptoms; can cause blood even without stones. |
| Kidney stones | Sudden, sharp pain in the side or tummy that comes and goes. See kidney and ureteric stones. |
| Injury | A fall, sports injury or blow to the tummy, side or back. |
| Inflammation of the kidney filters (glomerulonephritis), including after a throat or skin infection | Brown or cola-coloured urine, puffy eyes or legs, passing less urine. |
| A blockage or structural problem in the urinary tract | Tummy or side pain, infections, sometimes found on an earlier scan. See PUJ obstruction in children. |
| Inherited conditions and blood clotting problems | Family history of kidney disease, deafness or bleeding problems. |
In one group of 228 children with visible blood and no other symptoms, quoted in the Scottish NHS guidance, high urine calcium was found in 22% and a kidney filter condition called IgA nephropathy in 16%, while 36% had no cause found.
How blood in urine is diagnosed in children
The doctor will ask about the colour, clots, recent infections, injuries, exercise, medicines and family history of kidney disease, and will check blood pressure, growth and any swelling. Tests, chosen according to the child, may include:
- Urine dipstick and microscopy to confirm red blood cells and look at their shape.
- Urine culture to look for infection.
- Urine protein and urine calcium measurements.
- Blood tests such as a blood count, kidney function and, in some children, complement proteins. See our page on kidney function tests.
- Ultrasound of the kidneys and bladder to look for stones, cysts, blockages and other changes.
- Testing family members’ urine, as some causes run in families.
For microscopic blood alone in a well child, the first step is usually to repeat the test. The Scottish NHS guidance defines persistent microscopic haematuria as blood in three samples taken at least a week apart, not after exercise. HealthyChildren.org notes that most children do not need a kidney biopsy, and that a camera test of the bladder (cystoscopy) is uncommon in children.
When it is urgent and when to see a doctor
Any visible blood in a child’s urine should be checked by a doctor, even if your child seems well. Seek medical help the same day, or go to an emergency department, if blood in the urine comes with:
- Fever, especially with pain in the back or side, or a baby who is feeding poorly.
- Severe tummy, side or back pain.
- Swelling of the face, eyes or legs, or passing much less urine than usual.
- An injury to the tummy, side, back or groin.
- Clots, or difficulty or inability to pass urine.
- Unusual drowsiness, irritability or low energy.
- A rash, bruising or joint pain.
Blood found by chance on a urine test in a well child is less urgent, but should be rechecked as the doctor advises.
When no cause is found
It is common for tests to find no cause. HealthyChildren.org says doctors cannot find the cause in about 1 in 4 cases. HealthyChildren.org advises yearly check-ups if blood persists, to watch for kidney disease, and the Child Kidney Diseases review also recommends regular follow-up. Treatment, when needed, depends entirely on the cause and is decided by the child’s doctor. The centre’s urologists see children and can assess blood in urine together with any other urinary symptoms; see our paediatric urology page.
Frequently asked questions
Is blood in a child's urine serious?
Often it is not. Many children have a minor cause such as a urine infection, exercise or high urine calcium, and microscopic blood often clears by itself. Visible blood still needs a doctor's check, and blood with fever, swelling, severe pain or reduced urine needs urgent care.
Can a urine infection cause blood in a child's urine?
Yes. A urine infection is one of the common causes in children. It often comes with fever, pain or stinging when passing urine and needing to go often. A urine sample is tested to confirm infection, and the doctor decides on treatment.
Can food make my child's urine look red?
Yes. Beetroot, some berries and food colourings can turn urine pink or red, and some medicines can change its colour too. A dipstick and microscope test shows whether real blood is present, so tell the doctor what your child has eaten recently.
What does microscopic haematuria mean in a child?
It means red blood cells are found on a urine test, but the urine looks normal. It is common in healthy children and often goes away within weeks. Doctors usually repeat the test before doing further investigations, unless there are other signs such as protein in the urine or high blood pressure.
Which doctor should see a child with blood in the urine?
Usually the family doctor or paediatrician first. Depending on the cause, a child may be referred to a paediatric kidney specialist, for example when there is protein in the urine or high blood pressure, or to a urologist when there are stones, a blockage or another structural problem.
References
- Blood in Urine (Hematuria) – HealthyChildren.org
- Haematuria, management and investigation in Paediatrics – NHSGGC
- Hematuria in children: causes and evaluation – Child Kidney Diseases (2024)
- Blood in urine (haematuria) – nidirect
Book a consultation
Prof. Samir Al-Samarrai and Dr. Amer Mousa assess urological conditions at Prof. Al-Samarrai Medical Center, Dubai Healthcare City, and discuss the options that suit your case. Medical consultations are confidential.
Read more: Urologist in Dubai: doctors, services, insurance and booking
This information is for health education and does not replace a medical examination. See our medical content policy.
Medically reviewed by: Prof. Dr. Samir Ahmed Al-Samarrai, consultant urologist. Review date: .
About the doctor
Prof. Dr. Samir Ahmed Al-Samarrai, consultant urologist. He studied medicine at the universities of Heidelberg and Johannes Gutenberg in Germany and graduated with distinction, earned his doctorate (PhD) with a research thesis in 1980, and on 23 August 1978 received his specialist certificate in the treatment and surgery of male urological diseases from the Free University of Berlin, at its medical school hospital, under the specialist regulations of the Berlin Chamber of Physicians.
Clinic: Prof. Al-Samarrai Medical Center, Al Razi Medical Complex 64, Building D, 2nd floor, No. 2018, Dubai Healthcare City, Dubai. MOHAP licence: ZGU3I12X-291225.
This article is for health education and does not replace a consultation with a doctor. Last updated: 6 November 2026.
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