A Single-centre Study of COVID-19 Antibody

Area of Science:

• Immunology
• Infectious Diseases
• Clinical Diagnostics

Background:

• The COVID-19 pandemic necessitated rapid development and deployment of diagnostic tests.
• Understanding antibody test performance and seroprevalence is crucial for public health management.
• The Roche Elecsys® Anti-SARS-CoV-2 assay is a widely used method for detecting antibodies.

Purpose of the Study:

• To evaluate the performance of the Roche Elecsys® Anti-SARS-CoV-2 total antibody assay.
• To determine the seroprevalence of SARS-CoV-2 antibodies in a walk-in patient population.
• To correlate antibody test results with symptoms and timing of testing.

Main Methods:

• Conducted 453 SARS-CoV-2 antibody tests using Roche Elecsys® kits on a Cobas® e411 analyser.
• Employed electrochemiluminescence immunoassay (ECLIA) for antibody detection.
• Collected samples from walk-in patients between June 13 and July 8, 2020.

Main Results:

• Out of 453 tests, 289 (63.8%) were reactive, 162 (35.8%) non-reactive, and 2 (0.4%) equivocal.
• Symptomatic individuals comprised 57.8% of reactive cases, while 6.0% were asymptomatic.
• The highest proportion of reactive cases (42.6%) were tested 15-21 days after symptom onset; fever was the most common symptom.

Conclusions:

• The Roche Elecsys® assay demonstrated a high reactivity rate in the tested population.
• Testing between 15-21 days post-symptom onset appears optimal for detecting SARS-CoV-2 antibodies.
• Seroprevalence data can inform public health strategies and understanding of infection dynamics.