Multicenter performance evaluation of the Elecsys HCV Duo immunoassay.

BACKGROUND: The diagnostic accuracy of the Elecsys® HCV Duo antigen-antibody combination immunoassay (Roche Diagnostics GmbH) was evaluated for the detection of hepatitis C virus (HCV) infection, versus commercially available comparators. METHODS: This multicenter study (August 2020-March 2021) assessed the specificity of the Elecsys HCV Duo immunoassay and comparator assays in blood donor and routine clinical laboratory samples; sensitivity was determined in confirmed HCV-positive samples and seroconversion panels. The Elecsys HCV Duo immunoassay was compared with the Monolisa HCV Ag-Ab ULTRA V2, Murex HCV Ag/Ab Combination and ARCHITECT HCV Ag assays, as well as nucleic acid testing (NAT). The antibody (anti-HCV) module of the Elecsys HCV Duo immunoassay was compared with the Elecsys Anti-HCV II, Alinity s Anti-HCV, ARCHITECT Anti-HCV and RIBA HCV 3.0 SIA assays. RESULTS: The specificity of the Elecsys HCV Duo immunoassay was 99.94% (95% confidence interval [CI], 99.89-99.97) and 99.92% (95% CI, 99.71-99.99) in blood donor (n = 20,634) and routine clinical laboratory samples (n = 2531), respectively. The specificity of the Elecsys HCV Duo immunoassay was similar or better than comparator assays. The sensitivity of the Elecsys HCV Duo immunoassay in confirmed HCV-positive samples (n = 257) was 99.6%. In seroconversion panels, the Elecsys HCV Duo immunoassay detected infections earlier (2.2-21.9 days) than all but one of the comparator assays and detected HCV 1.8 days later than NAT. CONCLUSIONS: The Elecsys HCV Duo immunoassay shows high diagnostic accuracy, reduces the diagnostic window, and could be used when NAT is not possible.

Multicenter Evaluation of a Fully Automated High-Throughput SARS-CoV-2 Antigen Immunoassay.

INTRODUCTION: Molecular testing for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to suffer from delays and shortages. Antigen tests have recently emerged as a viable alternative to detect patients with high viral loads, associated with elevated risk of transmission. While rapid lateral flow tests greatly improved accessibility of SARS-CoV-2 detection in critical areas, their manual nature limits scalability and suitability for large-scale testing schemes. The Elecsys® SARS-CoV-2 Antigen assay allows antigen immunoassays to be carried out on fully automated high-throughput serology platforms. METHODS: A total of 3139 nasopharyngeal and oropharyngeal swabs were collected at 3 different testing sites in Germany. Swab samples were pre-characterized by reverse transcription real-time polymerase chain reaction (RT-qPCR) and consecutively subjected to the antigen immunoassay on either the cobas e 411 or cobas e 801 analyzer. RESULTS: Of the tested respiratory samples, 392 were PCR positive for SARS-CoV-2 RNA. Median concentration was 2.95 × 104 (interquartile range [IQR] 5.1 × 102-3.5 × 106) copies/ml. Overall sensitivity and specificity of the antigen immunoassay were 60.2% (95% confidence interval [CI] 55.2-65.1) and 99.9% (95% CI 99.6-100.0), respectively. A 93.7% (95% CI 89.7-96.5) sensitivity was achieved at a viral RNA concentration ≥ 104 copies/ml (~ cycle threshold [Ct] value < 29.9). CONCLUSION: The Elecsys SARS-CoV-2 Antigen assay reliably detected patient samples with viral loads ≥ 10,000 copies/ml. It thus represents a viable high-throughput alternative for screening of patients or in situations where PCR testing is not readily available.

Performance evaluation of the Roche Elecsys Anti-SARS-CoV-2 S immunoassay.

The Elecsys® Anti-SARS-CoV-2 S immunoassay (Roche Diagnostics International Ltd, Rotkreuz, Switzerland) has been developed for the detection of antibodies to the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein. We evaluated the assay performance using samples from seven sites in Germany, Austria, and Switzerland. For specificity and sensitivity analyses, 7880 presumed negative pre-pandemic samples and 827 SARS-CoV-2 PCR-confirmed single or sequential samples from 272 different patients were tested, respectively. The overall specificity and sensitivity (≥14 days post-PCR) for the Elecsys Anti-SARS-CoV-2 S immunoassay were 99.95% (95% confidence interval [CI]: 99.87-99.99; 7876/7880) and 97.92% (95% CI: 95.21-99.32; 235/240), respectively. The Elecsys Anti-SARS-CoV-2 S immunoassay had significantly higher specificity compared with the LIAISON® SARS-CoV-2 S1/S2 IgG (99.95% [2032/2033] vs 98.82% [2009/2033]), ADVIA Centaur® SARS-CoV-2 Total (100% [928/928] vs 86.96% [807/928]), ARCHITECT SARS-CoV-2 IgG (99.97% [2931/2932] vs 99.69% [2923/2932]), iFlash-SARS-CoV-2 IgM (100.00% [928/928] vs 99.57% [924/928]), and EUROIMMUN Anti-SARS-CoV-2 IgG (100.00% [903/903] vs 97.45% [880/903]) and IgA (100.00% [895/895] vs 95.75% [857/895]) assays. The Elecsys Anti-SARS-CoV-2 S immunoassay had significantly higher sensitivity (≥14 days post-PCR) compared with the ARCHITECT SARS-CoV-2 IgG (98.70% [76/77] vs 87.01% [67/77]), iFlash-SARS-CoV-2 IgG (100.00% [76/76] vs 93.42% [71/76]) and IgM (100.00% [76/76] vs 35.53% [27/76]), and EUROIMMUN Anti-SARS-CoV-2 IgG (98.26% [113/115] vs 93.91% [108/115]) assays. Therefore, the Elecsys Anti-SARS-CoV-2 S assay demonstrated a reliable performance across various sample populations for the detection of anti-S antibodies.

Multicentre Performance Evaluation of the Elecsys Anti-SARS-CoV-2 Immunoassay as an Aid in Determining Previous Exposure to SARS-CoV-2.

INTRODUCTION: We performed a multicentre evaluation of the Elecsys® Anti-SARS-CoV-2 immunoassay (Roche Diagnostics), an assay utilising a recombinant protein representing the nucleocapsid (N) antigen, for the in vitro qualitative detection of antibodies to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). METHODS: Specificity was evaluated using serum/plasma samples from blood donors and routine diagnostic specimens collected before September 2019 (i.e., presumed negative for SARS-CoV-2-specific antibodies); sensitivity was evaluated using samples from patients with polymerase chain reaction (PCR)-confirmed SARS-CoV-2 infection. Point estimates and 95% confidence intervals (CIs) were calculated. Method comparison was performed versus commercially available assays. RESULTS: Overall specificity for the Elecsys Anti-SARS-CoV-2 immunoassay (n = 9575) was 99.85% (95% CI 99.75-99.92): blood donors (n = 6714; 99.82%), routine diagnostic specimens (n = 2861; 99.93%), pregnant women (n = 2256; 99.91%), paediatric samples (n = 205; 100.00%). The Elecsys Anti-SARS-CoV-2 immunoassay demonstrated significantly higher specificity versus LIAISON SARS-CoV-2 S1/S2 IgG (99.71% vs. 98.48%), EUROIMMUN Anti-SARS-CoV-2 IgG (100.00% vs. 94.87%), ADVIA Centaur SARS-CoV-2 Total (100.00% vs. 87.32%) and iFlash SARS-CoV-2 IgM (100.00% vs. 99.58%) assays, and comparable specificity to ARCHITECT SARS-CoV-2 IgG (99.75% vs. 99.65%) and iFlash SARS-CoV-2 IgG (100.00% vs. 100.00%) assays. Overall sensitivity for Elecsys Anti-SARS-CoV-2 immunoassay samples drawn at least 14 days post-PCR confirmation (n = 219) was 93.61% (95% CI 89.51-96.46). No statistically significant differences in sensitivity were observed between the Elecsys Anti-SARS-CoV-2 immunoassay versus EUROIMMUN Anti-SARS-CoV-2 IgG (90.32% vs. 95.16%) and ARCHITECT SARS-CoV-2 IgG (84.81% vs. 87.34%) assays. The Elecsys Anti-SARS-CoV-2 immunoassay showed significantly lower sensitivity versus ADVIA Centaur SARS-CoV-2 Total (85.19% vs. 95.06%) and iFlash SARS-CoV-2 IgG (86.25% vs. 93.75%) assays, but significantly higher sensitivity versus the iFlash SARS-CoV-2 IgM assay (86.25% vs. 33.75%). CONCLUSION: The Elecsys Anti-SARS-CoV-2 immunoassay demonstrated very high specificity and high sensitivity in samples collected at least 14 days post-PCR confirmation of SARS-CoV-2 infection, supporting its use to aid in determination of previous exposure to SARS-CoV-2.