Initial Evaluation of a Mobile SARS-CoV-2 RT-LAMP Testing Strategy.

Area of Science:

• Virology
• Molecular Diagnostics
• Public Health

Background:

• Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) control is challenged by testing limitations.
• Current testing often requires specialized laboratory settings.

Purpose of the Study:

• To evaluate a simple, outdoor, mobile colorimetric reverse-transcription loop-mediated isothermal amplification (RT-LAMP) assay for SARS-CoV-2 RNA detection.
• To assess the assay's performance using self-collected saliva samples.

Main Methods:

• A total of 4704 surveillance samples were collected from volunteers at 5 outdoor sites between July 16 and November 19, 2020.
• Samples were tested using a colorimetric RT-LAMP assay with self-collected saliva.
• False-negative rate was estimated by pooling RT-LAMP-negative samples and re-testing with quantitative reverse-transcription polymerase chain reaction (qRT-PCR).

Main Results:

• The RT-LAMP assay showed 98.8% concordance with qRT-PCR.
• Only 5 of 421 RT-LAMP-negative pools (2493 samples) tested positive by qRT-PCR, indicating a low false-negative rate.
• The assay successfully identified positive cases, including those who would not typically qualify for symptom-based testing.

Conclusions:

• A rapid, mobile, outdoor RT-LAMP assay using saliva is effective for SARS-CoV-2 detection.
• This method can be implemented outside traditional laboratories by personnel with basic molecular biology skills.
• The assay can aid in identifying asymptomatic individuals, improving public health surveillance and control efforts.