New Simplified Rapid COVID-19 Testing Protocol Requires Less Labor, Expertise and Equipment

A simplified COVID-19 testing protocol that offers a distinct advantage over the standard viral or universal transport medium (VTM) can detect minimal quantities of the SARS-CoV-2 using samples from both upper respiratory tract swabs (nasal and throat) as well as saliva, and can be used in research laboratories with minimal molecular biology equipment and expertise.

The testing protocol developed by researchers at the Schmidt College of Medicine at Florida Atlantic University (Boca Raton, FL, USA) aims to meet the urgent need for introducing alternative reagents and approaches to provide nucleic-acid testing in the face of heightened demand and potential shortages. The protocol utilizes TRIzol (guanidinium thiocyanate/phenol-chloroform) to purify the viral RNA from different types of clinical specimens, requires minimal biosafety level precautions and, given its high sensitivity, can be easily adapted to pooling samples strategies. Using this simplified protocol, samples are eluted in TRIzol immediately after collection and RNA is extracted. Results have shown that this protocol is as efficient, if not more than the CDC-approved silica-membrane based RNA purification microcolumns in isolating small amounts of viral and cellular RNA from multiple types of samples (nasal and throat swabs and saliva).

With this new approach, samples are first pooled and tested; positive pools are then retested individually. This relatively simple solution decreases the testing resources used but results in a loss in sensitivity from diluting positive patient samples with negative ones, hence the need of highly-sensitive tests that utilize biological materials, like saliva, which can be obtained in larger amounts and can be easily preserved for re-testing. The protocol uses common chemical reagents that are in abundant supply and can isolate high-quality RNA that can be utilized for multiple assays and RNA sequencing projects. In addition, samples in TRIzol can be preserved at 4 C for more than a week with minimal degradation and little to no loss of viral RNA. Moreover, the ability to use saliva samples, which are as- or more sensitive and reliable than nasopharyngeal swabs, offers an attractive specimen alternative.

“The high sensitivity of our protocol may be useful in testing patients with low viral titers such as asymptomatic patients or testing individuals prior to quarantine release. Our method also enables several patient samples to be pooled, decreasing the number of tests required for larger populations,” said Massimo Caputi, Ph.D., lead author and a professor of biomedical science in FAU’s Schmidt College of Medicine. “In addition, testing can easily be carried out by any research laboratory equipped with minimal standard equipment. Since saliva can be utilized as a reliable source of virus, samples can be self-obtained by patients and inactivated in TRIzol, eliminating the need for medical staff and higher-level biosafety protocols and facilities.”

Related Links:
Florida Atlantic University