A negative urinalysis rules out catheter-associated urinary tract infection in trauma patients in the intensive care unit

Background: Urinary tract infection (UTI) in trauma patients is associated with increased mortality. Whether the urinalysis (UA) is an adequate test for a urinary source of fever in the ICU trauma patient has not been demonstrated. We hypothesized that the UA is a valuable screen for UTI in the febrile, critically ill trauma patient. Study Design: All trauma ICU patients in our surgical ICU who had a fever (temperature >38.0 C), urinary catheter, UA, and a urine culture between January 1, 2011 and December 13, 2011 were reviewed. A positive UA was defined as positive leukocyte esterase, positive nitrite, WBC > 10/high power field, or presence of bacteria. A positive urine culture was defined as growth of ≥10⁵ colony forming units (cfu) of an organism irrespective of the UA result or ≥10³ cfu in the setting of a positive UA. A UTI was defined as positive urine culture without an alternative cause of the fever. Results: There were 232 UAs from 112 patients that met criteria. The majority (75%) of patients were men; the mean age was 40 (±16) years. Of the 232 UAs, 90 (38.7%) were positive. There were 14 UTIs. The sensitivity, specificity, positive predictive value, and negative predictive value of the UA for UTI were 100%, 65.1%, 15.5%, and 100%, respectively. Conclusions: A negative UA reliably excludes a catheter-associated UTI in the febrile, trauma ICU patient with a 100% negative predictive value, and it can rapidly direct the clinician toward more likely sources of fever and reduce unnecessary urine cultures.