Researchers validate clinical feasibility for COVID-19 testing

A team of researchers from the University of Connecticut validated the clinical feasibility of the All-In-One-Dual CRISPR-Cas12a (AIOD-CRISPR) method for rapid, ultrasensitive, visual detection of SARS-CoV-2, the virus that causes the novel coronavirus (COVID-19), intended for use at home or in small clinics, according to a new paper published in the journal Nature Communications. Additionally, the researchers used a low-cost hand warmer as an incubator to detect clinical sample results within 20 minutes.

For the study, researchers evaluated the AIOD-CRISPR method using the RNA extract of 28 clinical COVID-19 swab samples, which included eight COVID-19 positive samples. To ensure the reliability of detection, each sample was tested twice in two independent trials. All eight of the COVID-19 positive samples were identified as positive in 40 minutes, which was also confirmed by visual detection. The results were also consistent with those of the CDC-approved RT-PCR method, the researchers said.

Nucleic acid amplification testing (PCR/RT-PCR) is currently the most sensitive and specific method for early detection of pathogens but is not suitable for rapid point-of-care diagnostics because of the need for specialized laboratory equipment and trained technicians. Highly contagious pathogens, however, need real-time monitoring to prevent spreading from person to person, according to the study.

The researchers also used a low-cost hand warmer as an incubator to detect the patient samples to eliminate the need for an electric incubator. The AIOD-CRISPR tubes were directly placed on an air-activated hand warmer, and the results were visible by the naked eye under LED light. Two COVID-19 positive samples incubated in the hand warmer bag were visually detected and identified as positive in 20 minutes, the study said.

“The usage of disposable hand warmers to heat the AIOD-CRISPR assay eliminates need for expensive electric equipment, enabling instrument-free point of care molecular diagnostics of COVID-19,” said Changchun Liu, PhD, lead author of the study and associate professor at the university, in a statement. “Such simple, portable, and sensitive detection platform has the potential to provide rapid and early diagnostics of COVID-19 and other infectious diseases at home, in doctor's office, and even at drive-thru testing sites.”

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