The Hologic Panther Fusion® Open Access™ system, a successfully developed and validated multiplex polymerase chain reaction (PCR), laboratory-developed test performed comparably to or better than a commercial reference assay [that received quality clearance from the European Union] in detecting norovirus G1, norovirus G2, and rotavirus, according to a study published in the European Journal of Clinical Microbiology & Infectious Diseases.

The Panther Fusion system allows laboratory-developed test to be implemented with fully automated extraction of samples, real-time PCR, and interpretation of the results. Of the various commercial assays currently available to detect and identify rotavirus and norovirus in stool samples, the platforms for real-time multiplex PCR assays are either not fully automated and/or low a throughput makes them less than ideal in clinical settings that require high efficiencies and productivity.

The Panther Fusion system is fully automated and has a high-throughput, sample-to-result in vitro diagnostic system capable of performing various tests using real-time PCR, transcription-mediated amplification, or real-time transcription-mediated amplification with an Open Access™ functionality. This allows real-time PCR laboratory-developed tests to be performed alongside in vitro diagnostic tests. In addition, the user only has to prepare the stool samples and the PPR mix and new samples can be loaded at any time via random continuous access. The time to results can be as short as 2.5 hours. Samples are processed five at a time, with results for 5 samples coming out every 5 minutes. The test also allows laboratories to transfer existing laboratory-developed tests and results on this system or develop new ones.

Investigators used the functionality of the Panther Fusion Open Access system to develop a multiplex laboratory-developed test for detecting norovirus G1, norovirus G2, and rotavirus in stool samples, and compared its clinical performance with that of a commercially available reference multiplex assay (Allplex™ GI-Virus Assay, Seegene). External quality assessment samples (Instand e.V., Düsseldorf, Germany) were tested to determine the sensitivity and specificity of the laboratory-developed test.

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Reproducible results were observed for PCR and the extraction process, and the sensitivity of the laboratory-developed test was comparable or superior to the commercial Allplex assay, with excellent linearity. All 45 external quality assessment samples yielded the expected laboratory-developed test results, and there was 100% concordance in results for 160 clinical samples between laboratory-developed test and Allplex. Results from both the direct swab and the suspension method for stool sample preparation were highly concordant in the laboratory-developed test, with the direct swab method showing higher sensitivity. Further, the sensitivity of rotavirus was comparable between the laboratory-developed test and Allplex, and was higher in the detection of norovirus in laboratory-developed tests compared with Allplex. There was an unexpected detection of norovirus in 1 sample that was positive for astrovirus (cycle threshold = 40.1), but this likely occurred because the sample had a low viral load that was not detected using the Allplex assay.

The investigators concluded, “Our noro-/rotavirus multiplex [laboratory-developed test] performed comparably or better in respect to specificity and specificity than a commercial, reference assay [that received quality clearance from the European Union], allowing for fast and reliable diagnostics in clinical routine.”

Disclosure: This study was supported by Hologic Inc. Please see the original reference for a full list of authors’ disclosures.

Reference

Kulis-Horn RK, Tiemann C. Evaluation of a laboratory-developed test for simultaneous detection of norovirus and rotavirus by real-time RT-PCR on the Panther Fusion® system [published online September 10, 2019]. Eur J Clin Microbiol Infect Dis. doi: 10.1007/s10096-019-03697-7