232. The Roche cobas® Liat FluA/B Assay: Filling the Need for a Simple, Sensitive, STAT PCR Test for Influenza
Session: Poster Abstract Session: Diagnostics: Virology
Thursday, October 8, 2015
Room: Poster Hall
  • Liat poster semi final 9-29_rev final.png (865.9 kB)
  • Background: We compared the performance of the Liat FluA/B assay (Roche Molecular, Branchburg, NJ) with that of our current test, the Focus Diagnostics 3M Simplexa FluA/B & RSV Kit (Cypress, CA; Simplexa).

    Methods: Following the manufacturer’s instructions, we analyzed directly 40 residual patient specimens that had been frozen in virus transport medium (Meridian, Cincinnati, OH). Aliquots had previously been extracted by MagNA Pure (Roche) and reported as Simplexa positive only for Flu A (20: winter 2013-2014, presumptive H1:N1; and 20: winter 2014-2015, presumptive H3:N2) or for FluB (10: winter 2014-2015). We also included 9 frozen patient samples that had tested positive for respiratory syncytial virus (RSV) but negative for both FluA and FluB by Simplexa.  

    Results: Among the 40 FluA-positive specimens, one was missed by Liat: it had a crossing threshold (CT) in the Simplexa assay of 37.1, indicating a low concentration of virus. When re-extracted and re-analyzed the discordant sample remained Simplexa-positive with a similar CT. The CTs of other specimens were lower suggesting the presence of higher concentrations of virus. An alternative molecular technique detected this organism and identified it as FluA, type H3. Overall sensitivity for FluA was 97.5%: 95% for 2013-2014 and 100% for 2014-2015. Liat detected 10/10 samples that were Simplexa positive for FluB (sensitivity: 100%).  Among 9 specimens reported by Simplexa as positive for RSV but negative for both FluA and FluB, none was reported as positive by Liat for either influenza virus. No dual FluA/B infection was reported by Liat. The specificities of Liat for FluA and for FluB were each 100%.

    Conclusion: Liat is a good candidate for a STAT molecular test for fluA/B. It is rapid, sensitive and specific, and requires no nucleic acid extraction or specialized molecular training. The analyzer is small (footprint: 11.4 x 24 cm) and light (3.76 Kg). Results are available in about 20 min, with 1 min hands-on time.  It is not presently classified as a waived test by the U.S. FDA.

    Hossein Salimnia, Ph.D.1,2, Marilynn Fairfax, M.D./Ph.D.1,2, Vandana Verma-Ahuja, MT(ASCP)1, Dawn Prebelich, MT(ASCP)1 and Paul Lephart, PhD1, (1)Detroit Medical Center University Laboratories, Detroit, MI, (2)Dept. of Pathology, Wayne St. Univ. Sch. of Med., Detroit, MI


    H. Salimnia, Nanosphere: Grant Investigator , Grant recipient and Research grant
    BioFire: Grant Investigator , Grant recipient and Research grant
    GenMark: Grant Investigator , Grant recipient and Research grant
    Accelerate: Grant Investigator , Grant recipient and Research grant
    AdvanDx: Grant Investigator , Grant recipient and Research grant

    M. Fairfax, None

    V. Verma-Ahuja, None

    D. Prebelich, None

    P. Lephart, None

    Findings in the abstracts are embargoed until 12:01 a.m. PDT, Wednesday Oct. 7th with the exception of research findings presented at the IDWeek press conferences.