Blood in Urine


My 3-year-old son was recently treated for a urinary tract infection, but during the follow-up the doctor noted that my son still has traces of blood in his urine. Could this be something other than a UTI?

Dr. Greene's Answer

Fever, back pain, and bacteria in the urine means that the urinary tract infection is not just in the bladder (cystitis) but also in the kidney (pyleonephritis). When blood is still present (called hematuria), it is important to find out what it looks like and why it is there. Urinary infections themselves can cause blood in the urine and the blood typically resolves as the infection resolves. There are several other causes for blood in the urine of a child, including kidney stones. A stone or a “pre-stone,” called hypercalciuria (too much calcium in the urine) can cause blood and pain.

About 5 to 10 percent of all kidney stones happen in kids. One bacterium that causes urinary infections (proteus) is also prone to cause stones. At a minimum, boys with this type of infection need a renal ultrasound and a VCUG (an x-ray taken during urination). If there is suspicion of a stone or hypercalciuria, then a blood test for calcium, phosphorus, uric acid, electrolytes, and parathyroid hormone should be performed. Further tests could include kidney studies (CT scan, ultrasound, and/or X-rays), urine for calcium:creatinine ratio, and a 24-hour urine collection to measure the total amount of calcium. This test isn’t performed for infections, but it is done to check for stones.

Last medical review on: May 14, 2008
About the Author
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Dr. Greene is a practicing physician, author, national and international TEDx speaker, and global health advocate. He is a graduate of Princeton University and University of California San Francisco.
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Recent Comments

My 6 year old son has blood in his urine which was picked up in a urine sample with the dip stick, the urine was sent away and they found some bacteria but was not a UTI. He was sent for an ultrasound which came back clear, the doctor has now referred us to a kidney specialist. I have no idea what could be causing this and would like some information as to what could be causing this as he was treated for a UTI two years ago.