266. Comparison of Nasopharyngeal versus Bronchoalveolar lavage specimens for detection of viral pathogens using a multiplex PCR assay
Session: Poster Abstract Session: Diagnostic Microbiology; Novel Molecular Methods
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C
Posters
  • IDSAposter2013RVPBAL.jpg (707.4 kB)
  • Background: Bronchoalveolar lavage (BAL) specimens have been reported to be the optimal specimen for detection of viral pathogens in lower respiratory tract infections.  However, nasopharyngeal (NP) flocked swab collection systems used in conjunction with a multiplex PCR assay have shown an increased yield of pathogens compared to standard NP collection and viral culture methods.  The objective of this study was to assess how a NP flocked swab compares to an invasive BAL specimen for detection of viral pathogens when using a multiplex PCR assay. 

    Methods: Retrospective review over 3 respiratory viral seasons (Oct-March 2010-11, 2011-12, 2012-13) of all respiratory viral panel (RVP) results where both an NP and BAL specimen were submitted within 0-7 days of each collection.  Specimens were analyzed using the Luminex X-tag RVP (Luminex, Austin, TX).  Rates of testing, pathogen detection, and comparison of NP versus BAL test parameters were compared.  Sub-group analysis of patients with discordant results was conducted to assess for potential factors associated with differing NP, BAL results.

    Results: A total of 87 patients had NP and BAL specimens sent for RVP analysis.  Overall concordance between sample sites was 87.4%.  In total, there were 56 cases (64.4%) where both NP and BAL were negative; 20 cases (23.0%) where both specimens were positive for the same viral pathogen.  Eleven patients (12.6%) had discordant results:  6 cases where NP testing was positive and BAL was negative and 5 cases of negative NP and positive BAL.  Median days between NP and BAL specimen obtainment between concordant and discordant results was 1.0 vs 3.0 days, respectively (p=0.068).  NP specimens detected a viral pathogen at a similar rate as BAL specimen (83.9% of pathogens detected via NP vs 80.6% via BAL, p=0.87).

    Conclusion:  In a case series of patients undergoing both BAL and NP specimen obtainment for RVP analysis, NP specimens detected a respiratory viral pathogen as often as testing from specimens obtained via bronchoalveolar lavage.  These data suggest that multiplex PCR analysis of nasopharyngeal specimens may be a reasonable non-invasive initial diagnostic test compared to BAL-derived specimens when evaluating critically-ill patients for respiratory viral pathogens.

    Russell Mcculloh, MD, Pediatrics, Division of Pediatric Infectious Disease, Hasbro Childrens Hospital, Brown University, Providence, RI, Roberta Dickenson, Rhode Island Hospital, Providence, RI and Kimberle C. Chapin, MD, Pathology, Warren Alpert Medical School of Brown University, Providence, RI

    Disclosures:

    R. Mcculloh, None

    R. Dickenson, None

    K. C. Chapin, None

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