Las Vegas Emergency Medicine - 7/13/2016 - By Aaron Heckelman
"Every day in the ED we see patients with vague, nonspecific abdominal pain, and in a lot of EDs a clean-catch urinalysis is part of these patients’ standard lab workup. And in a lot of ED’s there is great variation in the way different providers interpret those urinalyses and decide who gets diagnosed with, and treated for, a UTI. So what does the evidence say about this? Not as much as you’d hope – despite being such a common laboratory test, data on how good urinalysis is at predicting UTI (defined by symptoms plus a positive urine culture) is surprisingly sparse and inconsistent. Hence all the practice variation. But after an extensive literature review, here are the best evidence-based answers I could produce to some questions we face every day in the ED.
Note that this literature review applies only to female adult patients. Laboratory definition of a “positive urine culture” varies a little between labs and studies, but usually is defined as a culture that grows out >104-105 colony forming units of a single organism. Definition of a “contaminated culture” similarly varies, but is usually one that grows out multiple organisms, or <104-105 of a single organism..."