Editor’s Note: Katie is a telephone triage nurse with a background in women’s and children’s health. She is also the mother of two neurodiverse teens with medical complexities. - Cara L. Coleman, JD, MPH
Parents who have their child evaluated for a possible urinary tract infection (UTI) may assume that the tests performed are accurate. In fact, current tests may often not be. This can cause problems if children who have UTIs are not treated, and for those who may be given antibiotics they don’t need.
In this month’s Pediatrics, “Accuracy of Screening Tests for the Diagnosis of Urinary Tract Infection in Young Children” by Shaikh et al. (10.1542/peds.2024-066600) and the associated commentary, “Re-examining the Role of Pyuria in UTI Diagnosis” (10.1542/peds.2024-068242) address how we test young children for UTI.
What types of testing can be done to look for UTI?
A urinalysis (UA) is a test that can be run quickly in a clinic or hospital. A person, a computer, or both look for certain cells in a urine sample. Results are usually available within minutes. However, seeing these cells on a urinalysis doesn’t always mean an infection is present. For this reason, it’s often used to decide whether a second test, a urine culture, is needed. A urine culture is done by placing a sample of urine into a plate of nutrients and waiting several days to see if bacteria grow.
What was the study looking for?
The Sheikh article looked at whether different ways of running a UA would make the test better at detecting UTI. The authors were specifically looking for pyuria, which means “white blood cells (WBC) in the urine.” They wanted to know if any of the five methods studied—some computerized and some done visually by humans—were a good way to identify children who have a UTI (as confirmed by a positive urine culture).
Why look for white blood cells in the urine?
White blood cells can signal infection, and a past guideline from the American Academy of Pediatrics (AAP) said high levels of white blood cells were needed to diagnose a UTI. However, it is now noted that bacteria can grow in urine without there being white blood cells in the urine. This guideline was retired in 2021.
Why does this matter?
Even though the guideline that requires high white blood cells in urine to order a urine culture has been retired, many places still follow it. This may miss quite a few UTIs.
Having a good test that can be performed at the time of symptoms is helpful because waiting for the culture results before you give antibiotics can allow the infection to get dangerously out of control.
How did they study this?
This study looked at urine samples from 4,188 children under the age of 3 years, from three US emergency departments. A urine culture that grew a certain amount of bacteria likely represented a “true” UTI, and this is the standard that the other methods were measured against.
What did the study find?
None of the ways of doing a UA led to more accuracy. One of the most common ways (if >10 white blood cells are seen in the urine) to decide whether a urine culture should be done missed 35% of children who turned out to have an infection.
The authors of the commentary share that there are currently other methods being studied that may someday increase the accuracy of early testing.
What can you do with this article?
- If your child has had UTIs, share this article with your doctor. Use it to start a conversation or to help ask questions about their treatment.
- If your child is being treated for a UTI (or was sent home without treatment) and is not improving, do not be afraid to call your doctor for help.
- If you know other families whose children have UTIs, share this article with them.
