Urine cultures are the most frequently ordered microbiologic test, with the majority of specimens submitted from asymptomatic patients. Urine cultures should only be ordered if patients have symptoms localizing to the urinary tract such as acute dysuria, urgency, frequency, suprapubic or flank pain or fever without an obvious alternate source. Outside of these specific symptoms, positive cultures indicate asymptomatic bacteriuria and frequently result in antimicrobial therapy that is of no benefit and is potentially harmful. Cloudy or malodorous urine are not specific findings of urinary tract infection and should not prompt culture unless acute urinary tract symptoms are present. Delirium is not considered a symptom of cystitis in non-catheterized patients. In catheterized patients with fever or delirium, a positive urine culture may still represent asymptomatic bacteriuria unless alternate sources have been excluded. Laboratories should consider supplementing educational efforts to reduce collection of urine cultures from asymptomatic patients with analytical interventions that reduce processing of low-value specimens.
Sources:
Hartley S, et al. Inappropriate testing for urinary tract infection in hospitalized patients: an opportunity for improvement. Infect Control Hosp Epidemiol. 2013 Nov;34(11):1204-7. PMID: 24113606.
Leis JA, et al. Reducing antimicrobial therapy for asymptomatic bacteriuria among noncatheterized inpatients: a proof-of-concept study. Clin Infect Dis. 2014 Apr;58(7):980-3. PMID: 24577290.
McKenzie R, et al. Bacteriuria in individuals who become delirious. Am J Med. 2014 Apr;127(4):255-7. PMID: 24439075.
Nicolle LE, et al. Practice Guideline for the Management of Asymptomatic Bacteriuria: 2019 Update by the Infectious Diseases Society of America. Clin Infect Dis. 2019 May 2; pii: ciy1121. doi: 10.1093/cid/ciy1121. [Epub ahead of print] PMID: 30895288.
Related Resources:
Toolkit: Give the Test a Rest: A toolkit for decreasing unnecessary emergency department laboratory testing