title: Influenza and respiratory syncytial virus detection in clinical specimens without nucleic acid extraction using FOCUS direct disc assay is substantially equivalent to the traditional methods and the FOCUS nucleic acid extraction-dependent RT-PCR assay.
abstract: In this study, we evaluated FOCUS diagnostic's Flu A/B & RSV direct kit (Direct Disc assay), designed to detect influenza (FLU) and respiratory syncytial viruses (RSV) directly in clinical specimens without nucleic acid extraction. This novel 'sample-to-answer', nucleic acid extraction-independent assay uses a unique disc to process, amplify, and detect viral targets in up to 8 specimens at a time. The performance of this assay for detecting FLU and RSV viruses was compared to the traditional methods (culture and/or direct florescent antibody testing) using 945 nasopharyngeal swab specimens. In addition, a total of 150 consecutive clinical specimens positive for FLU (FLU A=50, FLU B=50) or RSV (n=50) were tested in parallel using the novel Direct Disc assay and FOCUS diagnostic's nucleic acid extraction-dependent assay to assess their relative performance. Compared to the traditional methods, the overall (prospective+retrospective) positive/negative percent agreement was determined to be 96.6%/98.1% for FLU A, 98.4%/99.9% for FLU B, and 99.3%/98.8% for RSV. Compared to the nucleic acid extraction-dependent assay, the positive percent agreement was 90% (n=45/50) for FLU A, 92% (n=46/50) for FLU B, and 98% (n=49/50) for RSV. Overall, the Direct Disc assay showed good agreement with both traditional methods and nucleic acid extraction-dependent assay. Although we encountered some failures compared to the nucleic acid extraction-dependent assay, these limitations must be balanced against the substantial advantages of the extraction-free nature of this assay and rapid turnaround time.
authors.affiliation: University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Suresh B
authors.initials: SB
authors.lastname: Selvaraju
authors.affiliation: Focus Diagnostics, Inc., Cypress, CA, USA.
authors.forename: David
authors.initials: D
authors.lastname: Tierney
authors.affiliation: Nationwide Children's Hospital, Columbus, OH, USA.
authors.forename: Amy L
authors.initials: AL
authors.lastname: Leber
authors.affiliation: Le Bonheur Children's Medical Center, Memphis, TN, USA.
authors.forename: Anami
authors.initials: A
authors.lastname: Patel
authors.affiliation: University of Rochester Medical Center, Rochester, NY, USA.
authors.forename: Amalia K
authors.initials: AK
authors.lastname: Earley
authors.affiliation: Focus Diagnostics, Inc., Cypress, CA, USA.
authors.forename: Dipeshkumar
authors.initials: D
authors.lastname: Jaiswal
authors.affiliation: University of Rochester Medical Center, Rochester, NY, USA. Electronic address: marilyn_menegus@urmc.rochester.edu.
authors.forename: Marilyn A
authors.initials: MA
authors.lastname: Menegus
mesh_terms: D000293:Adolescent; D000328:Adult; D001315:Australia; D002648:Child; D002675:Child, Preschool; D004279:DNA, Viral / Q000302:isolation & purification*; D005260:Female; D006801:Humans; D009981:Influenza B virus / Q000302:isolation & purification*; D007251:Influenza, Human / Q000175:diagnosis; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D060888:Real-Time Polymerase Chain Reaction / Q000379:methods*; D018357:Respiratory Syncytial Virus Infections / Q000175:diagnosis; D012136:Respiratory Syncytial Viruses / Q000302:isolation & purification*; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013048:Specimen Handling; D014481:United States; D055815:Young Adult
chemical_list: D004279:DNA, Viral
keywords: Direct Disc assay; FOCUS nucleic acid extraction–dependent assay; Flu and RSV detection; Nasopharyngeal swab specimens; Simplexa