Comparison of the Idylla™ Respiratory (IFV-RSV) panel with the GeneXpert Xpert® Flu/RSV assay: a retrospective study with nasopharyngeal and midturbinate samples.
Author(s): Wouters Y, Keyaerts E, Rector A, Van Even E, Vissers S, Koletzki D, Pattery T, Rousseau E, Van Ranst M, Laffut W
Publication: Diagn Microbiol Infect Dis, 2019, Vol. 94, Page 33-37
PubMed ID: 30638655 PubMed Review Paper? No
Purpose of Paper
This paper compared the detection of respiratory viruses by real-time RT- PCR in midturbinate and nasopharyngeal swab specimens using two different assays (Idylla Respiratory (IFV-RSV) panel and GeneXpert Xpert Flu/RSV assay).
Conclusion of Paper
Results were concordant between the two assays for 343 of the 354 nasopharyngeal specimens and 317 of the 325 midturbinate specimens and between 302 of the 321 of the paired specimens for both assays.
Studies
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Study Purpose
This study compared the detection of respiratory viruses by real-time RT- PCR in midturbinate and nasopharyngeal swab specimens using two different assays. A total of 354 nasopharyngeal and 325 mid‐turbinate swabs were collected from 358 patients (paired specimen types collected from 321 patients) presenting with influenza-like illness during the influenza season of 2015-2016. Specimens were stored frozen at -80°C in Universal Transport Medium after routine testing. Specimens were thawed, mixed, and brought to room temperature 2 h before detection of influenza A (H1, AH3, and H1N1), influenza B, and respiratory syncytial virus (RSV) using two different multiplex real-time RT-PCR assay. The positive percentage agreement (PPA) and a negative percentage agreement (NPA) of respiratory virus detection using the Idylla Respiratory (IFV-RSV) panel was compared to the GeneXpert Xpert Flu/RSV assay and results between specimen types were compared. Paired specimens were analyzed by both assays simultaneously or within a maximum of 1 h. Cases with discordant results were sent to a reference lab for confirmative testing using an in-house RT-PCR assay.
Summary of Findings:
Results were concordant between the two assays for 343/354 nasopharyngeal specimens and for 317/325 midturbinate specimens with a positive percentage agreement (PPA) using GeneXpert as the reference of 100.00% and 98.15% for influenza A, respectively; 96.23% and 98.29% for influenza B, respectively; and 100.00% for RSV for both assays. Negative percentage agreement (NPA) for influenza A, influenza B, and RSV was 98.98%, 100.00%, and 98.83% in nasopharyngeal specimens; respectively, and 99.63%, 98.27%, and 100.00% for midturbinate specimens; respectively. For the 321 paired specimens, 302 produced concordant results between the two assays. Using the nasopharyngeal specimens as the control, PPA for influenza A, influenza B, and RSV detection by the IFV-RSV panel was 88.52%, 94.06%, and 42.86% and NPA was 100.00%, 99.54%, and 100.00%; respectively. Similarly, the PPA for influenza A, influenza B, and RSV using the GeneXpert assay was 89.83%, 88.57%, and 75%; respectively, and the NPA was 99.62%, 100%, and 100%; respectively. All discordant results resolved by in-house RT-PCR testing agreed with the assay that detected the virus.
Biospecimens
Preservative Types
- Frozen
Diagnoses:
- Pneumonia/Respiratory Infection
Platform:
Analyte Technology Platform RNA Real-time qRT-PCR Pre-analytical Factors:
Classification Pre-analytical Factor Value(s) Real-time qRT-PCR Specific Technology platform GeneXpert Xpert Flu/RSV assay
Idylla Respiratory (IFV-RSV) panel
Biospecimen Acquisition Biospecimen location Nasopharynx
Midturbinate