Evaluation of the sample-to-result, random access NeuMoDx platform for viral load testing of Cytomegalovirus and Epstein Barr virus in clinical specimens

Diagnosing viral gastro-enteritis using the fully automated sample-in, result-out STARlet All in one system (AIOS)

The STARlet All-In-One system is a modular platform that integrates the complete molecular diagnostic workflow from nucleic acid extraction of clinical samples to PCR set-up and amplification. The platform was evaluated in comparison with laboratory developed tests (LDT) on fecal samples from patients with suspected viral gastro-enteritis. In a retrospective study, 72 positive samples were analysed, including all pathogens detected by the Seegene Allplex™ GI-virus assay, adenovirus, astrovirus, norovirus GI and GII, sapovirus, and rotavirus. Concordant results were obtained for 69 samples (96 %). Three discordant results were observed, one norovirus GII positive that gave an invalid result in the AIOS and two samples that were negative in the AIOS. One adenovirus positive that was subtyped as a genotype 2 virus, which is not associated with gastro-enteritis, and a sapovirus. In the prospective part of the study, 661 fecal samples were included. A total of 61 positive samples were detected, of which 60 were also detected by the AIOS. One norovirus GII positive sample (CT 35.2) was tested negative in the AIOS. Two additional sapovirus positive samples, CT 37 and 38, were detected by the AIOS but not by the LDT. The STARlet All-In-One platforms results in an automated molecular workflow with reduced hands-on time and enables running assays during out of office hours. Application of the Seegene Allplex™ GI-virus assay showed excellent concordance to the current diagnostic LDT. In a prospective comparison, only three discordant results were observed, all with CT values over 35 and therefore unlikely of clinical relevance.

Analytical and Clinical Performance of the NeuMoDx™ Platform for Cytomegalovirus and Epstein-Barr Virus Viral Load Testing

DNA assays for viral load (VL) monitoring are key tools in the management of immunocompromised patients with cytomegalovirus (CMV) or Epstein-Barr virus (EBV) infection. In this study, the analytical and clinical performances of the NeuMoDx™ CMV and EBV Quant Assays were compared with artus CMV and EBV QS-RGQ Kits in a primary hospital testing laboratory. Patient plasma samples previously tested using artus kits were randomly selected for testing by NeuMoDx assays. The NeuMoDx CMV Quant Assay and artus CMV QS-RGQ Kit limits of detection (LoDs) are 20.0 IU/mL and 69.7 IU/mL, respectively; 33/75 (44.0%) samples had CMV DNA levels above the LoD of both assays. The Pearson correlation coefficient was 0.9503; 20 samples (60.6%) had lower NeuMoDx CMV quantification values versus the artus kit. The LoD of the NeuMoDx EBV Quant Assay and artus EBV QS-RGQ Kit are 200 IU/mL and 22.29 IU/mL, respectively; 16/75 (21.3%) samples had EBV DNA levels above the LoD of both assays. The Pearson correlation coefficient was 0.8990. EBV quantification values with the NeuMoDx assay were higher versus the artus kit in 15 samples (93.8%). In conclusion, NeuMoDx CMV and EBV Quant Assays are sensitive and accurate tools for CMV and EBV DNA VL quantification.

Performance Evaluation of the Fully Automated NeuMoDx RT-PCR Platform for the Quantification of CMV and EBV DNA in EDTA Plasma: Implications for Clinical Management and Establishment of a Conversion Formula

The NeuMoDx96 platform is a fully automated real-time PCR (RT-PCR) system. To provide continued testing quality with the introduction of new assays, the primary aim of this study was to evaluate the analytical and clinical performance of the NeuMoDx platform for the detection and quantification of CMV and EBV DNA in EDTA plasma. As no conversion from log₁₀ international units per milliliter to copies per milliliter was provided, the secondary aim was to calculate and establish a conversion factor for the output of results in copies per milliliter for CMV and EBV. Archived ETDA plasma samples (cytomegalovirus [CMV], n = 290; Ebstein-Barr virus [EBV], n = 254) were used to evaluate the analytical performance of the NeuMoDx96 platform against the routine real-time quantitative PCR (qPCR) assays. Additionally, the first WHO international standards (WHO-IS) for CMV (n = 70) and EBV (n = 72) were used for the calculation of the intra- and interassay variation. WHO-IS qualitative agreement between the assays was 100%. Intra-assay variability was low for both CMV assays (coefficient of variation [CV], phosphate-buffered saline [PBS], 3 log₁₀ IU/mL NeuMoDx, 3.67%; Abbott RealTime, CMV, 3.35%) and NeuMoDx EBV assay (CV, PBS, 3 log₁₀ IU/mL, 3.05%) but high for the Altona EBV assay (CV, PBS, 3 log₁₀ IU/mL, 26.13%). The overall qualitative concordance in clinical samples was 96.8% (270/279) for CMV and 96.7% (237/245) for EBV. The mean difference between the assays was -0.2 log₁₀ IU/mL (CMV) and -0.18 log₁₀ IU/mL (EBV). High qualitative concordance and a significant correlation of quantitative values for both assays make NeuMoDx CMV and EBV assays suitable for routine diagnostic testing. The new RT-PCR system and conversion formulas to report results in copies per milliliter are now applied in clinical routine testing. IMPORTANCE Clinical management of solid organ transplant (SOT) patients requires the careful monitoring of immunosuppression and viral infection or reactivation. qPCR is the gold standard for the detection and quantification of very small amounts of viral DNA and allows for an early assessment of viral load kinetics. The tested NeuMoDx 96 platform provides faster results than the previously used RT-PCR workflows for CMV (Abbott m2000 and RealTime CMV assay) and EBV (LightCycler 480 II, Roche high pure extraction, and Altona RealStar EBV assay) DNA detection. The implemented conversion formulas allow the continued reporting in clinically established copies per milliliter, important for long-term care of SOT patients.