A Lateral Flow Immunoassay Coupled with a Spectrum-Based Reader for SARS-CoV-2 Neutralizing Antibody Detection

Area of Science:

• Immunology
• Medical Diagnostics
• Biotechnology

Background:

• Over 200 million COVID-19 cases and 4 million deaths globally by August 2021.
• Serological assays are valuable for COVID-19 diagnosis, especially in recovered or late-stage patients.
• Lateral flow immunoassays (LFIA) offer advantages over traditional ELISA but require objective interpretation.

Purpose of the Study:

• To develop an innovative, portable device for accurate interpretation of LFIA results.
• To improve the diagnostic accuracy of neutralizing antibody detection for SARS-CoV-2.
• To assess the feasibility of the developed system for both COVID-19 patients and vaccinated individuals.

Main Methods:

• Developed a spectrum-based portable reader to capture high-resolution reflectance spectra from LFIA.
• Combined the spectrum-based reader with commercial LFIA kits.
• Tested the system on serum samples from 30 COVID-19 patients and plasma samples from 16 AstraZeneca-vaccinated individuals.

Main Results:

• The coupled system achieved an area under the ROC curve of 0.989.
• Demonstrated 100% sensitivity, 95.7% positive predictive value, 87.5% specificity, and 100% negative predictive value in COVID-19 patients.
• Showed a high correlation with ELISA in vaccinated individuals, indicating broad applicability.

Conclusions:

• The spectrum-based reader coupled with LFIA is a valuable tool for accurate neutralizing antibody detection.
• This approach significantly enhances diagnostic accuracy compared to visual interpretation of LFIA.
• The system is a feasible method for detecting neutralizing antibodies in both COVID-19-infected and vaccinated populations.