PD33-02: Negative urinalysis accurately predicts absence of uropathogen growth on culture and absence of urinary tract infection in premenopausal females
Introduction: Urine culture is associated with over one quarter of U.S. hospitalizations, and unnecessary antibiotic prescription is a main driver of antibiotic resistance. We sought to assess predictive value of a negative urinalysis for negative urine culture and absence of urinary tract infection, re-evaluate the threshold of microbial growth for positive urine culture result, and describe antimicrobial resistance features. Methods: Urinalyses with associated urine culture from women ages 18-49 from 2013 to 2020 were studied. Clinically-diagnosed urinary tract infection (CUTI) was defined as 1) culture growth of a uropathogen, 2) recorded diagnosis of urinary tract infection, and 3) antibiotic prescription. Sensitivity, specificity, and diagnostic predictive values were used to assess urinalysis performance in the prediction of isolation of a uropathogen by culture and in detection of CUTI. Results: 12,252 urinalyses were included. 41% of urinalyses were associated with positive urine culture and 10.5% with CUTI. Negative urinalysis accurately predicted negative urine culture (specificity 90.3%, PPV 87.3%) and absence of CUTI (specificity 92.2%, PPV 97.4%, Table). 39 out of 40 individuals with a negative urinalysis did not have a CUTI. 24% of patients who did not meet the CUTI definition were still prescribed antibiotics. 22% of cultures associated with CUTI had culture growth less than 100,000 CFU/ml. Escherichia coli was implicated as causing 70% of CUTIs, and 4.2% of these produced an extended spectrum beta-lactamase. Conclusions: Negative urinalysis is highly accurate in predicting the absence of CUTI in the premenopausal female population. The reporting threshold of 10,000 CFU/ml is more clinically appropriate than the commonly-used 100,000 CFU/ml cutpoint. Our findings support using urinalysis screening and reflex urine culture to complement clinical judgement in this population. This approach would have helped to improve laboratory stewardship, antibiotic stewardship, and time to final laboratory results. The predictive value of urinalysis in patients with neurologic pathology, recurrent or chronic UTI, men, children, and older individuals warrants future study. SOURCE OF Funding: N/A
