Analysis of SARS-CoV-2 antibodies from dried blood spot samples with the Roche Elecsys Immunochemistry method

Objectives: The aim of this study was to evaluate the application of the Roche Elecsys anti-SARS-CoV-2 assay to capillary dried blood samples for high throughput analyses on Roche COBAS 6000 systems.

Design and methods: The performance of the of the Elecsys anti-SARS-CoV-2 assay was assessed using three sets of dried blood spot samples. Method correlation was performed using spiked blood samples. Sensitivity and specificity were calculated using paired donor samples. An additional cohort of 50 individuals, including COVID-19 convalescent cases, was used for the evaluation of at-home collection for mail transport, and stability studies.

Results: The Elecsys anti-SARS-CoV-2 assay using dried blood spot samples showed an excellent agreement of 98.9% with results obtained using their paired serum samples, and 86.7% accuracy with dried blood spots collected after 9 days from diagnostic (PCR) tests.

Conclusions: Capillary dried blood spot samples can be confidently used on Roche COBAS automated analyzers to monitor the epidemiology of COVID-19, and are suitable for use in large-scale screening programs.