Dataset Information

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

ABSTRACT:

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 [C_t] 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.

SUBMITTER: Norz D

PROVIDER: S-EPMC8351226 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:BackgroundCyclosporine A (CsA) is used as a posttransplantation immunosuppressant drug, and careful monitoring of CsA concentration in whole blood is essential. A new automated electrochemiluminescence immunoassay (ECLIA) for CsA measurement has been assessed in a multicenter evaluation.MethodsResidual EDTA whole blood samples from patients undergoing CsA therapy after organ transplant were used in assay evaluation at 5 clinical laboratories in Europe. Experiments included imprecision according to CLSI EP5-A2 (within-run and intermediate), lower limit of quantification, linearity according to CLSI EP6-A, and recovery of commercial external quality control samples. In addition, comparisons to liquid chromatography-tandem mass spectrometry methods in routine use at each investigational site and to commercial chemiluminescent microparticle immunoassay and antibody-conjugated magnetic immunoassay methods were performed.ResultsImprecision testing gave coefficients of variation of less than 9% in the 30-2000 mcg/L range for both within-run and intermediate imprecision. Lower limit of quantification of 6.8 mcg/L at one investigational site and 1.8 mcg/L at a second site at 20% coefficient of variation were observed. Linearity was measured over the concentration range 0-2000 mcg/L, yielding a deviation of less than ±12%. External quality control sample recovery by ECLIA was 93%-114% of LC-MS/MS sample recovery. Deming regression analysis of ECLIA method comparison to combined LC-MS/MS results yielded a slope of 1.04 [95% confidence interval (CI), 1.03-1.06] and intercept of 2.8 mcg/L (95% CI, 1.5-4.1 mcg/L). Comparison to chemiluminescent microparticle immunoassay yielded a slope of 0.87 (95% CI, 0.85-0.89) and intercept of 1.4 mcg/L (95% CI, -0.89 to 3.7 mcg/L); comparison to antibody-conjugated magnetic immunoassay yielded a slope of 0.96 (95% CI, 0.93-0.98) and intercept of -4.2 mcg/L (95% CI, -7.1 to -1.2 mcg/L).ConclusionsThe data from this multicenter evaluation indicate that the new ECLIA-based cyclosporine assay is fit for its purpose, the therapeutic monitoring of CsA.