Evaluation of a laboratory-developed test for simultaneous detection of norovirus and rotavirus by real-time RT-PCR on the Panther Fusion® system

The Hologic Panther Fusion® Open Access™ functionality allows implementation of laboratory-developed tests (LDTs), with fully automated sample extraction, real-time PCR, and result interpretation. We report the development and validation of a multiplex LDT for norovirus G1, norovirus G2, and rotavirus from stool samples on this system. The LDT was optimized for primer and probe sequences, salt concentration, and PCR annealing temperature. Reproducibility of the PCR and extraction process was assessed. Performance of the multiplex LDT assay was evaluated with external quality assessment (EQA) samples and compared to a commercial multiplex assay (Allplex™ GI-Virus Assay, Seegene) in clinical samples. Salt concentrations and annealing/extension temperature were optimized to 4 mM MgCl(2), 70 mM KCl, 20 mM Tris, and 60 °C, respectively. The user-prepared part of the LDT PCR mix (containing salts, probes, and primers) was stable for ≥ 11 days onboard the instrument. We observed reproducible results of PCR and the extraction process. The LDT had a sensitivity comparable to or greater than the commercial Allplex™ assay and showed excellent linearity. Forty-five EQA samples yielded the expected result with the LDT. There was 100% concordance between LDT and Allplex™ results in 160 clinical samples. Results from the suspension and direct swab stool sample preparation methods were highly concordant in the LDT. We report the successful development and validation of a multiplex PCR LDT for detection of norovirus G1, norovirus G2, and rotavirus from stool samples on the Panther Fusion® system. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (10.1007/s10096-019-03697-7) contains supplementary material, which is available to authorized users.