Comparison of Two Multiplex Methods for Detection of Respiratory Viruses: FilmArray RP and xTAG RVP

Abstract

We compared the FilmArray RP (Idaho Technology, Inc., Salt Lake City, UT) and the xTAG RVP (Luminex Corporation, Toronto, Canada) multiplex respiratory virus PCR methods for the detection of respiratory viruses in a set of 200 patient specimens frozen at ؊70°C after standard viral culture and antigen detection methods were done. Both systems detected between 40 to 50% more viruses than traditional methods, primarily rhinoviruses and human metapneumovirus. The FilmArray RP detected significantly more total viruses either alone or as part of mixed infections than the xTAG RVP, as well as an additional 21.6% more respiratory syncytial viruses. The xTAG RVP requires 5 to 6 h with 2.5 to 3 h of hands-on time, while the FilmArray RP takes about an hour with 3 to 5 min of hands-on time, making it much easier to perform.Multiplex reverse transcriptase respiratory virus PCR has been shown to be more sensitive than standard respiratory virus culture, direct fluorescent-antigen, and direct enzymelinked immunosorbent assay (ELISA) antigen detection methods (1, 2, 7-9, 13-14, 16, 20). Viral culture is labor-intensive, detects some viruses (e.g., rhinovirus and coronavirus) poorly, and requires 3 to 5 days to detect most agents. Consequently, results are generally not available early in the clinical decisionmaking process. Direct fluorescent-antibody assay (DFA) and chromatographic immunoassays are rapid enough to support real-time clinical decisions, but DFA is highly labor-intensive and chromatographic immunoassays are relatively insensitive. The FilmArray RP multiplex respiratory virus panel uses a pouch system that contains all reagents for the identification of 18 respiratory viruses and 3 bacterial respiratory pathogens in about 1 h after inoculation of a patient sample, obviating both labor and turnaround time (TAT) issues. We compared the performance of the FilmArray RP with that of the FDAcleared Luminex xTAG RVP multiplex panel by using 200 retrospective clinical respiratory virus culture samples.

Real-Time PCR Assay for Detection and Differentiation of Shiga Toxin-Producing Escherichia coli from Clinical Samples

“…Also, after thawing, freezerarchived direct stool specimens were diluted approximately 1 part specimen to 3 parts Protocol Cary-Blair transport medium (Thermo Scientific, Middletown, VA), according to the manufacturer's recommendations (BioFire). The RM-PCR is characterized by a two-step process consisting of a primary single multiplex PCR followed by an array of organismspecific monoplex second-stage PCRs; it has high analytical sensitivity and specificity, as well as rapid turnaround time (22), and it is currently approved to detect 11 bacterial, 5 viral, and 4 protozoal confirmed or candidate pathogens, including Campylobacter, Clostridium difficile, Salmonella, Vibrio spp., Vibrio cholerae, Yersinia enterocolitica, enteroaggregative E. coli (EAEC), enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), STEC, Shigella/enteroinvasive E. coli (EIEC), adenovirus F40/41, astrovirus, norovirus GI/GII, rotavirus A, sapovirus, Cryptosporidium, Cyclospora cayetanensis, Entamoeba histolytica, and Giardia lamblia.…”

Clinical Evaluation of the Luminex NxTAG Respiratory Pathogen Panel

“…Various commercial molecular diagnostic assays, especially emerging multiplex technologies which detect and identify multiple respiratory pathogens, have been adopted by clinical microbiology laboratories. These molecular assays differ in the number of targets covered, test throughput, hands-on time, the need for nucleic acid extraction, instrumentation, and performance (1,7,8).…”

“…The xTAG Respiratory Viral Panel (RVP) (Luminex Molecular Diagnostics, Toronto, Canada) was the first FDA-cleared multiplexed molecular assay for respiratory pathogens, and it targets 12 viruses and virus subtypes, including respiratory syncytial viruses (RSVs) A and B, influenza A virus (subtypes H1 and H3 and untypeable), influenza B virus, parainfluenza viruses (PIVs) 1, 2, and 3, human metapneumovirus (hMPV), adenovirus, and enterovirus/rhinovirus (7)(8)(9). Although it has a high throughput volume per run, the xTAG RVP has a minimal specimen-to-result time of 5 to 6 h and requires an actual hands-on time of approximately 2.5 to 3 h. In addition, as an open system platform, there is potential risk for cross-contamination after specimen extraction and PCR amplification steps (7,8).…”

Evaluation of the Cepheid Xpert Flu Assay for Rapid Identification and Differentiation of Influenza A, Influenza A 2009 H1N1, and Influenza B Viruses

“…Commercial assays range from those that detect only influenza A and B viruses to those that detect as many as 15 viral pathogens (18)(19)(20)22). The identification of other viral respiratory pathogens can still be important in the inpatient setting, since knowledge of the etiologic agent can be a factor relevant to the overall clinical management of a patient.…”