Multi-center evaluation of the Research Use Only NeuMoDx monkeypox virus (MPXV) fully automated real-time PCR assay

The mpox outbreak, caused by monkeypox virus (MPXV), accelerated the development of molecular diagnostics. In this study, we detail the evaluation of the Research Use Only (RUO) NeuMoDx MPXV assay by multiple European and US sites. The assay was designed and developed by Qiagen for the NeuMoDx Molecular Systems. Primers and probes were tested for specificity and inclusivity in silico. The analytical sensitivity of the assay was determined by testing dilutions of synthetic and genomic MPXV DNA. A total of 296 clinical samples were tested by three sites; the Johns Hopkins University (US), UZ Gent (Belgium, Europe), and Hospital Universitario San Cecilio (Spain, Europe). The analytical sensitivity of the assay was 50 copies/mL for both clades I and II. The assay showed 100% in silico identity for 80 clade I and 99.98% in silico identity for 5,162 clade II genomes. Clade II primers and probes showed 100% in silico specificity; however, identity of at least one of the two sets of clade I primers and probes with variola, cowpox, camelpox, and vaccinia viruses was noticed. The clinical validation showed sensitivity of 99.21% [95% confidence interval (CI): 95.66-99.98%] and specificity of 96.64% (95% CI: 91.62-99.08%) for lesion swab samples. The NeuMoDx MPXV Test shows acceptable analytical and clinical performance. The assay improves the laboratory's workflow as it consolidates nucleic acid extraction, PCR, data analysis, and interpretation and can be interfaced. The Test Strip can differentiate clades I and II, which has important laboratory safety implications.

IMPORTANCE

In this manuscript, we provide detailed in silico analysis and clinical evaluation of the assay using a large cohort of clinical samples across three academic centers in Europe and the United States. Because the assay differentiates MPXV clades I and II, this manuscript is timely due to the current need to rule out the regulated clade I by diagnostic clinical laboratories. In December 2023, and due to first report of cases of sexually transmitted clade I infections in the Democratic Republic of the Congo, when generic assays that do not differentiate the clades are used, samples are considered regulated. The assay meets the need of full automation and has a marked positive impact on the laboratory workflow.

Real-world performance of the NeuMoDx™ HCV Quant Test for quantification of hepatitis C virus (HCV)-RNA

Quantification of hepatitis C virus (HCV)-RNA in serum or plasma samples is an essential parameter in HCV diagnostics. Here, the NeuMoDx™Molecular System (Qiagen) was tested for the most common HCV genotypes and compared to the cobas c6800 system (Roche). HCV-RNA from 131 plasma/serum samples from chronically infected patients was determined in parallel on the NeuMoDx and c6800 systems. Linearity was analysed using the four most common HCV genotypes (1-4) in our cohort. The coefficient of variation (CV) within (intra-assay) and between (inter-assay) runs was calculated based on HCV-RNA concentration. Quantitative HCV-RNA results were highly correlated on both test systems (R2 = 0.7947; y = 0.94 x + 0.37). On average, the NeuMoDx and c6800 HCV RNA levels showed a mean difference of only 0.05 log10 IU/mL but with a broad distribution (±1.2 2 x SD). The NeuMoDx demonstrated very good linearity across all HCV genotypes tested at concentrations between 1.7 and 6.2 log10 IU/mL (R2 range: 0.9257-0.9991) with the highest mean coefficient of determination for genotype 1 (R2 = 0.9909). The mean intra- and inter-assay CV for both serum and plasma samples was <5 %. The NeuMoDx HCV-RNA Assay demonstrates high subtype-independent comparability, linearity, and reproducibility for the quantification of HCV-RNA in serum and plasma samples from chronically infected patients.

Performance evaluation of NeuMoDx 96 system for hepatitis B and C viral load

BACKGROUND

Hepatitis B virus (HBV) and hepatitis C virus (HCV) viral load (VL) estimation is essential for the management of both HBV and HCV infections. Due to a longer turnaround time for VL estimation, many patients drop out from the cascade of care. To achieve the global goals of reducing morbidity and mortality due to HBV/HCV and moving towards their elimination by 2030, molecular diagnostic platforms with faster and random (i.e. single sample) access are needed.

AIM

To evaluate the performance of the recently launched NeuMoDx 96 random access system with the conventional COBAS®AmpliPrep/COBAS TaqMan system for HBV and HCV VL estimation.

METHODS

Archived once-thawed plasma samples were retrieved and tested on both platforms. Correlation between the assays was determined by linear regression and Bland-Altman analysis. The study included samples from 186 patients, 99 for HBV of which 49 were true infected HBV cases (hepatitis B surface antigen, anti-hepatitis B core antibody, and HBV DNA-positive) and 87 for HCV assay in which 39 were true positives for HCV infection (anti-HCV and HCV RNA-positive).

RESULTS

The median VL detected by NeuMoDx for HBV was 2.9 (interquartile range [IQR]: 2.0-4.3) log10 IU/mL and by COBAS it was 3.70 (IQR: 2.28-4.56) log10 IU/mL, with excellent correlation (R2 = 0.98). In HCV, the median VL detected by NeuMoDx was 4.9 (IQR: 4.2-5.4) log10 IU/mL and by COBAS it was 5.10 (IQR: 4.07-5.80) log10 IU/mL with good correlation (R2 = 0.96).

CONCLUSION

The overall concordance between both the systems was 100% for both HBV and HCV VL estimation. Moreover, no genotype-specific bias for HBV/HCV VL quantification was seen in both the systems. Our findings reveal that NeuMoDx HBV and HCV quantitative assays have shown overall good clinical performance and provide faster results with 100% sensitivity and specificity compared to the COBAS AmpliPrep/COBAS TaqMan system.

Implementation and clinical evaluation of an Mpox virus laboratory-developed test on a fully automated random-access platform

While Mpox virus (MPXV) diagnostics were performed in specialized laboratories only, the global emergence of Mpox cases in 2022 revealed the need for a more readily available diagnostic. Automated random-access platforms with fast nucleic acid extraction and PCR have become established in many laboratories, providing faster and more accessible testing. In this study, we adapted a previously published generic MPXV-PCR as a lab-developed test (LDT) on a NeuMoDx Molecular System and isolated MPXV clones from patient materials. To reduce the handling of infectious material, we evaluated a viral lysis buffer (VLB) for sample pretreatment. We further compared the MPXV-LDT-PCR to conventional real-time PCR, determined its sensitivity and specificity using positive swabs, and assessed its performance using external quality assessment samples. Pretreatment of samples with 50% VLB reduced MPXV infectivity by approximately 200-fold while maintaining PCR sensitivity. The assay demonstrated a sensitivity and specificity of 100% with no cross-reactivity in the samples tested and performed with a limit of detection of 262 GE/mL. In summary, the assay had a turnaround time of fewer than 2 h and can easily be transferred to other automated PCR platforms, providing a basis for developing rapid assays for upcoming pandemics.

Validation of the NeuMoDx™ SARS-CoV-2 assay with COPAN eNAT® and E&O Viral PCR Sample Solution collection media types in comparison with other validated SARS-CoV-2 RNA assays

OBJECTIVES

This study aimed to confirm NeuMoDx™ SARS-CoV-2 assay (NeuMoDx assay) functionality using off-label collection media, determine assay performance versus other SARS-CoV-2 RNA assays, and assess any cross-reactivity with other respiratory viruses (human coronavirus NL63, influenza, and respiratory syncytial virus).

METHODS

Nasopharyngeal swab samples in off-label collection media and external quality assessment (EQA) samples were dual-tested, first using either the RealStar® SARS-CoV-2 reverse transcriptase polymerase chain reaction assay or the QIAstat-Dx® Respiratory SARS-CoV-2 Panel and then using the NeuMoDx assay. Samples found to be positive for respiratory viruses and negative for SARS-CoV-2 were then tested using the NeuMoDx assay to assess cross-reactivity.

RESULTS

Overall, 274 samples (244 patient and 30 EQA samples) were dual-tested; 154 were SARS-CoV-2 positive and 120 were negative. No false-positive or false-negative results were identified, regardless of collection medium used. The NeuMoDx assay sensitivity was 100% (95% confidence interval [CI] 97.63-100.00) and the specificity was 100% (95% CI 96.97-100.00). The assay did not exhibit any cross-reactivity with other respiratory viruses.

CONCLUSION

The NeuMoDx assay demonstrated high sensitivity and specificity on a platform well-suited for fully automated SARS-CoV-2 testing.

Comparison of the clinical sensitivity and specificity of two commercial RNA SARS-CoV-2 assays

Objectives

This study aimed to compare the performance of the NeuMoDx™ SARS-CoV-2 Assay, implemented on the NeuMoDx 96 Molecular System, with that of the ThermoFisher TaqPath™ COVID-19 CE-IVD RT-PCR Kit (reference method).

Methods

Overall, 450 nasopharyngeal swab samples, previously tested using the reference method, were tested by the NeuMoDx Assay, and the clinical sensitivity and specificity of the assay were analyzed.

Results

By retrospective statistical analysis of all valid results, the NeuMoDx Assay had a clinical specificity of 100% (95% confidence interval [CI]: 98.65–100.00) and a clinical sensitivity of 98.73% (95% CI: 95.47–99.85).

Conclusions

The NeuMoDx SARS-CoV-2 Assay demonstrated comparable analytical and clinical performance to the ThermoFisher TaqPath COVID-19 CE-IVD RT-PCR Kit. The NeuMoDx 96 Molecular System is well suited for automating medium-throughput routine SARS-CoV-2 testing or as an addition to high-throughput systems to allow fast-tracking for highly urgent clinical samples.

Cytomegalovirus Viral Load in Transplanted Patients Using the NeuMoDx™ (Qiagen) Automated System: A 1-Month Experience Feedback

Cytomegalovirus (CMV) reactivations represent a significant morbidity and mortality problem in transplant patients. Reliable and rapid measurement of CMV viral load is a key issue for optimal patient management. We report here the evaluation of NeuMoDx™ (Qiagen) in a routine hospital setting (University Hospitals of Marseille, France) in comparison with our classical reference technique R-GENE. During one month, 719 CMV viral loads from 507 patients were measured in parallel in both techniques. Using the ROC (receiver operating characteristic) curve and our biological experience we suggest that values <52 IU/mL (geometric mean) correspond to negative samples, values >140 IU/mL (Fowlkes–Mallows index) correspond to quantifiable positive results and values ranging from 52 to 140 IU/mL represent non-quantifiable positive results. Follow-up of 15 transplant patients who developed CMV reactivation during the study showed that NeuMoDx™ provided higher viral load measurement during the first two weeks of follow-up for three patients. These important intra-individual variations resulted in a significant median increase considering the whole data set (6.7 points of difference expressed as a percentage of the initial viral load). However, no difference between the two techniques was noticeable after two weeks of treatment. Subsequent to this first study we conclude that NeuMoDx™, used with optimized logistics and an adapted threshold, allows a rapid CMV viral load measurement and that its use does not lead to any difference in patient management compared to the reference technique R-GENE^®.

Multicenter evaluation of the NeuMoDx™ SARS-CoV-2 Test

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SARS-CoV-2 molecular assays are the current gold standard for diagnosis and large scale screening.

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Performance of the highly automated high throughput NeuMoDx assay for SARS-CoV-2 was evaluated.

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Data collected from three centers: Johns Hopkins Hospital, St. Jude Children’s Research Hospital, and the Wadsworth Center.

The SARS-CoV-2 virus has caused millions of confirmed COVID-19 cases worldwide and hundreds of thousands of deaths in less than 6 months. Mitigation measures including social distancing were implemented to control disease spread, however, thousands of new cases continue to be diagnosed daily. To resume some suspended social activities, early diagnosis and contact tracing are essential. To meet this required diagnostic and screening capacity, high throughput diagnostic assays are needed. The NeuMoDx™ SARS-CoV-2 assay, performed on a NeuMoDx molecular system, is a rapid, fully automated, qualitative real-time RT-PCR diagnostic test with throughput of up to 288 tests in an 8 -h shift. The assay received emergency use authorization from the FDA and is used in some large testing centers in the US. This paper describes the analytical and clinical performance of the assay at three centers: Johns Hopkins Hospital, St. Jude Children’s Research Hospital, and the Wadsworth Center.

Clinical evaluation of a SARS-CoV-2 RT-PCR assay on a fully automated system for rapid on-demand testing in the hospital setting

BACKGROUND

The ongoing SARS-CoV-2 pandemic presents a unique challenge for diagnostic laboratories around the world. Automation of workflows in molecular diagnostics is instrumental for coping with the large number of tests ordered by clinicians, as well as providing fast-tracked rapid testing for highly urgent cases. In this study we evaluated a SARS-CoV-2 LDT for the NeuMoDx 96 system, a fully automated device performing extraction and real-time PCR.

METHODS

A publicly available SARS-CoV-2 RT-PCR assay was adapted for the automated system. Analytical performance was evaluated using in-vitro transcribed RNA and clinical performance was compared to the cobas 6800-based reference assay within the lab.

RESULTS

The Envelope (E) Gene-LDT displayed good analytical performance with an LoD of 95.55 cp/mL and no false positives during evaluation of cross-reactivity. A total of 176 patient samples were tested with both the E-Gene-LDT and the reference assay. Positive and negative agreement were 100 % and 99.2 % respectively. Invalid-rate was 6.3 %.

CONCLUSION

The E-Gene-LDT showed analytical and clinical performance comparable to the cobas6800-based reference assay. Due to its random-access workflow concept and rapid time-to-result of about 80 min, the system is very well suited for providing fast-tracked SARS-CoV-2 diagnostics for urgent clinical samples in the hospital setting.