SESSION TITLE: Quality & Clinical Improvement Posters II
SESSION TYPE: Original Investigation Poster
PRESENTED ON: Wednesday, October 29, 2014 at 01:30 PM - 02:30 PM
PURPOSE: Streptococcus pneumoniae is a leading cause of community acquired pneumonia. The Binax Now Urinary Antigen Test (UAT) can aid rapid diagnosis. Usefulness of test in clinical setting remains unknown. We characterized UAT diagnostic yield in a sample of patients from a large tertiary hospital.
METHODS: This was a retrospective chart review. All adult patients admitted to Hackensack University Medical Center (HUMC) from December 2010 to August 2011 and had a UAT performed. HUMC laboratory data were used to identify patients. Data collected included age, sex, result of UAT, and when available, patient's demographics, sputum culture, blood culture, and imaging results.
RESULTS: Of 356 patients admitted with respiratory complaints, the UAT was positive in 14 samples (3.9%). Of the available data for cultures, sputum was positive in none of the samples and blood was positive for 1 sample. Rate of UAT positivity did not vary by age, gender or referral site. The UAT was positive in one of 80 patients with health care associated pneumonia (.012%), nine of 191 patients with community acquired pneumonia (.045%), and one of 48 immunocompromised patients (.02%). Sensitivity of UAT was found to be 1, specificity was 0.97 but the positive predictive value was 11% and negative predictive value was 100% based on blood cultures (257 patients). Sensitivity was 0, specificity 0.98, positive predictive value 0 and negative predictive value 1 based on sputum culture (128 patients). Sensitivity was 0, specificity 0.805, positive predictive value 0 and negative predictive value 0.57 based on imaging (116 patients).
CONCLUSIONS: In our study, UAT and other studies for pneumococcal disease had a low diagnostic yield. The UAT was specific, but sensitivity and positive predictive value were low. Study did not account for whether UAT was sent according to IDSA/ATS guidelines. This may reflect changes in pneumococcal prevalence in hospitalized patients, timing of when UAT was sent, and/or overuse of UAT in low probability patients. Further investigation is needed to determine the role of UAT in diagnosis of pneumococcal pneumonia.
CLINICAL IMPLICATIONS: Low diagnostic yield and mixed performance for UAT may reflect a different prevalence of S. pneumonia in our patient population and suggests potential clinician competence and practice deficits in its use. Further investigation is needed to determine the role of UAT in the diagnosis of pneumococcal pneumonia in routine practice as well cost analysis for the test.
DISCLOSURE: The following authors have nothing to disclose: Aesha Jobanputra, Shashi Kapadia, Lata Cherath, Hayder Hashim
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