Extraction-Free Testing for SARS-CoV-2 in Nasal Swab and Saliva Samples on a Single High-Throughput Platform.

Area of Science:

• Virology
• Molecular Diagnostics
• Public Health

Background:

• The COVID-19 pandemic necessitated rapid, high-throughput SARS-CoV-2 testing.
• RNA extraction is a significant bottleneck in traditional RT-qPCR assays.
• Developing streamlined diagnostic methods is crucial for pandemic preparedness.

Purpose of the Study:

• To describe a semi-automated, extraction-free RT-qPCR assay for SARS-CoV-2 detection.
• To evaluate the performance and scalability of this novel assay.
• To assess its suitability for large-scale diagnostic testing and surveillance.

Main Methods:

• Development of a semi-automated, extraction-free RT-qPCR assay for SARS-CoV-2.
• Testing of nasal swab and saliva samples on a single platform.
• Performance evaluation against established nucleic acid extraction methods.

Main Results:

• The assay demonstrated a limit of detection of 4 copies/mL.
• Performance was equivalent to methods requiring nucleic acid extraction.
• Over 400,000 samples were processed in 10 months with high throughput.
• Higher SARS-CoV-2 detection rates were observed in saliva (10.1%) compared to nasal swabs (7.7%).

Conclusions:

• The extraction-free RT-qPCR assay is a cost-effective and scalable solution for SARS-CoV-2 detection.
• This method addresses the bottleneck of RNA extraction, enabling rapid, high-throughput testing.
• The assay is well-suited for pandemic preparedness, surveillance, and diagnostic applications.