Cath or bag? Bag then cath? Urine testing options in the ED

Fever is a common chief complaint in young children. Many of these children will not have an obvious source. In those without obvious examination findings the necessity of obtaining diagnostic labs is often discussed amongst providers and with parents. This may or may not include evaluation for UTI. The majority of these children are not potty-trained meaning catheterization is often needed for obtaining the urine specimen which can be time-intensive, uncomfortable and stressful for families and children. Many of us have been taught that catheterization is the only way to get a sterile urine (well, not only as you can do a suprapubic aspiration). But what if there was another way?

How do we determine who needs urinalysis in the first place. Infants under 2 months with fever generally undergo more aggressive work-ups. Even up to 6 months, the risk of associated bacteremia is enough to likely warrant a work-up if no clear source in many cases. But what about babies over six months? There is the common risk stratification using gender, age, circumcision in males and so on but this still leaves a large number of children needing urinalysis. The idea of using bagged urine specimens is often tossed aside since it cannot be used for culture (skin contamination) and to do both once the work up has begun is also time consuming. Despite that, the AAP does maintain that a 2-step process (badge specimen – if positive then cath) is an option.

A recent study sought to investigate whether or not we should be going to caths first or if a bagged specimen was an appropriate initial screen. This study, which was conducted in a large pediatric hospital noted that 63% of children who presented with fever under the age of two underwent urethral catheterization. Of those, less than 5% had positive cultures.

The overall goal of this study was to investigate the possibility of reducing the number of urine catheterizations being performed. Patients in the ED with a complaint of fever between the ages of 6-24 months were risk stratified (see attached table below from study). Patients determined to be at increased risk had urine bags placed by a nurse on arrival to an ED room.  Urinalysis was performed at the discretion of the clinician after exam and full history obtained. If the urinalysis was positive for moderate or large leukocyte esterase or contained nitrites, the child then underwent catheterization for urine to be sent for culture.

The result was a reduction in catheterization rates from 63% of febrile children 6-24 months prior to approximately 30% while maintaining that 69% underwent UTI screening. 16% of children underwent catheterization as the primary method of urinalysis after the intervention. Of the remainder, only 14% had urine catheterization to obtain a urine culture specimen after a positive screen via bag specimen. There was no increase in revisit rate following the intervention or in the median ED length of stay.

So what does this mean for those of us not currently in an ED using this 2-step process? On a busy night, when a well appearing patient is brought back with a chief complaint of fever in the 6 month to 2 year age group, consider asking the nurse to place a urine bag when they go in for their assessment if fever has lasted more than 48 hours and fever was over 38.5 C. Then after further exam and history, there is the ability to have a urine sample readily available that could be sent for urinalysis if deemed appropriate. The results could help guide further work-up and determine if catheterization for a urine sample is necessary.

One caveat is that the aforementioned study did not look at the 2-step urinalysis approach effects on time in department and cost in an Emergency Department that does not have an integrated screening process (i.e. you have to send U/A’s up to a central lab – increasing time in department) so it may prove to be ineffective and time consuming if not utilized early in a patient’s ED stay.

Minimal Criteria for Urine Collection

References

Lavelle, J. M., Blackstone, M. M., Funari, M. K., Roper, C., Lopez, P., Schast, A., Shaw, K. N. (2016). Two-Step Process for ED UTI Screening in Febrile Young Children: Reducing Catheterization Rates. Pediatrics,138(1). doi:10.1542/peds.2015-3023.