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Kidney & Urinary System

Blood in the Urine (Hematuria)

Lea este articulo en EspanolBlood in the urine, known as hematuria (hee-ma-TUR-ee-uh), is fairly common and, in most cases, not serious.

The two kinds of hematuria are:

  1. Microscopic hematuria is when blood in the urine (pee) is not visible to the naked eye, and can only be detected through a urine test. In most cases, kids and teens who get microscopic hematuria will never know they had it, and it goes away without causing any damage or long-term problems.
  2. Gross hematuria is when there are enough red blood cells in the urine to turn it red or tea-colored. Many cases of gross hematuria also clear up on their own with no problems, but sometimes it’s a sign of a more serious condition. In those cases, doctors will treat the underlying cause.

How the Urinary Tract Works

The urinary tract is made up of two kidneys, two ureters, one bladder, and one urethra. Kidneys are fist-sized organs in the back that are shaped like kidney beans. It’s the kidneys’ job to filter the blood and remove excess fluids and waste products, which it turns into urine. The urine then flows through tubes called ureters into the bladder, where it’s stored until it’s emptied through a small tube called the urethra. If blood cells leak into the urine at any part of the process, it causes hematuria.


A number of things can cause hematuria, including:

  • bladder or kidney infections
  • kidney stones
  • mineral imbalances in the urine
  • abnormal development of any part of the urinary tract
  • menstruation
  • injuries to the kidneys or urinary tract
  • taking certain medicines, like some over-the-counter pain relievers
  • vigorous exercise (many athletes, especially distance runners, get hematuria from time to time)

In rare cases, hematuria can be a sign of kidney or bladder cancer, a blood disease, or a blood clot. If something like that is going on, hematuria will usually be one of many other symptoms.

Very occasionally, what looks like hematuria might be something else. It’s possible that things like food dye, beets, or certain medications can make a person’s pee look red.

Signs & Symptoms

Technically speaking, hematuria is a symptom. Microscopic hematuria has no visible signs. The only way doctors know if someone has microscopic hematuria is if it shows up on a urine test. Gross hematuria can be seen because it changes the color of urine, which can happen with just a little bit of blood. In many cases, red or tea-colored urine is the only symptom.

In more serious cases, hematuria can be just one of many symptoms of another condition. For instance, if a bladder infection is causing the hematuria, other symptoms might include fever, pain while urinating, and lower belly pain.


If you ever see blood in your child’s urine, don’t panic. Chances are it’s no big deal, but you’ll want to make sure, so take your child to see a doctor. It’s important to determine the cause of the hematuria to decide whether any treatment is necessary.

If you see a doctor about blood in your child’s urine, or if microscopic hematuria shows up on a urine test, the doctor will give your child a physical examination and ask questions about symptoms, recent activities, and family medical history. Your child will be asked for a urine sample as well.

If the urine test comes back negative, the doctor will probably want another urine sample 1-2 weeks later, just to make sure the urine is free of red blood cells. Hematuria that only happens once won’t require any follow-up with the doctor.

If microscopic hematuria is present but your child has no other symptoms (like pain or fever) and no protein in the urine, a urine test will be repeated several times over the next few months to see if blood continues to show up in the urine.

If the urine test points to something more serious, or if your child has had a recent injury, additional tests may be done. These can include a urine culture, or imaging tests like an MRI or CT scan that let doctors examine the urinary tract.

When to See a Specialist

Kids who have hematuria and protein in the urine should see a specialist. So should those with microscopic hematuria that doesn’t go away after a few months, or microscopic hematuria with high blood pressure and other symptoms. A specialist will offer additional testing to help determine the cause of blood in the urine.

Testing may include:

  • blood tests to determine kidney function
  • urine tests to check for protein, calcium, and creatinine (a waste product found in urine)
  • kidney ultrasound
  • kidney biopsy (removing a tiny sample of tissue for testing)
  • cystoscopy (a procedure that lets doctors see the inside of the urethra and bladder using a thin, tube-like instrument with a tiny camera on the end)


Most of the time, hematuria doesn’t require any treatment. If it only happens once, it’s nothing to worry about. If another condition is causing the blood in the urine, treatment for the hematuria will involve treating that condition. This may involve the use of certain medications, such as antibiotics for hematuria caused by a urinary tract infection (UTI).

Follow-up testing is often done after treatment to make sure the urine is free of red blood cells. If blood shows up in the urine repeatedly but there are no other symptoms, urine testing and physical exams may be done every few months for a year or more as a precautionary measure.

Reviewed by: Robert S. Mathias, MD
Date reviewed: May 2013