First Handheld COVID-19 Nucleic Acid Test Detects Positive Sample in 15 Minutes

By LabMedica International staff writers
Posted on 15 Feb 2022

Image: Pluslife Mini Dock (Photo courtesy of Pluslife Biotech)

A handheld POCT nucleic acid testing product for COVID-19 reaches very high level of sensitivity, specificity and accuracy, which is similar as qPCR test, and can also stably detect viruses at a very low LoD (Limit of Detection).

Pluslife Mini Dock, developed by Pluslife Biotech (Guangzhou, China), is the first handheld POCT nucleic acid testing product for COVID-19. Although rapid antigen test is simple and convenient to use, its sensitivity is significantly lower than that of qPCR test. In most cases, it can only detect strong positive samples, and if the concentration of viruses contained in the samples does not reach a certain number, there will be a probability of false negatives. Thus, in the early phases of infection, qPCR test is more accurate than antigen test.

Compared to rapid antigen test, the sensitivity and specificity of nucleic acid test are far superior, and it can also detect infected patients at a much earlier stage. However, current common nucleic acid test like qPCR test requires expensive instruments and cumbersome operation processes, so the tests are primarily used in hospitals, third-party testing centers or laboratories. As such, qPCR test is not conducive to obtaining test results immediately at community-based testing sites. Traditional qPCR products rely on elevated temperatures and have high hardware requirements, resulting in the overall high cost of the instruments; while the majority of the existing isothermal nucleic acid testing can address the cost issue and have faster amplification speed, but they cannot stably reach good sensitivity and specificity, which make them unable to be directly benchmarked with qPCR, so for a long time there was no well-formed POCT nucleic acid testing that could be applied to families as well as community health clinics.

To develop its POCT nucleic acid testing product, Pluslife Biotech developed RHAM, an underlying technology with independent intellectual property rights, which is different from the traditional isothermal amplification technologies such as LAMP or CRISPR detection technology. RHAM technology shows similar performance as qPCR, and is much better than the traditional isothermal amplification technologies (like LAMP) in terms of sensitivity, stability and specificity. The wider tolerance and better compatibility of RHAM realize the one-step operation of sample processing, amplification and detection all-in-one. This process does not involve actions such as opening the lid after the amplification (no aerosol contamination), and has low requirements for external environment and hardware support.

Pluslife Mini Dock addresses the existing problems of dependence on expensive instruments and can achieve on-site nucleic acid testing at the grassroots level and obtain test results immediately. In terms of testing method, after taking the anterior nasal swab sample, users simply put the swab into the lysate and the test card, and then insert the test card into the Mini Dock for one-step testing and get results. In terms of testing efficiency, Pluslife Mini Dock can detect a positive sample in about 15 minutes and confirm a negative sample in 35 minutes, significantly reducing the waiting time compared to the qPCR test (usually 3-4 hours with extraction, not including sample transfer time to the lab). In terms of cost, the cost of Pluslife Mini Dock is much more affordable than other POCT nucleic acid testing instruments in the market, and it is also reusable, making it suitable for large-scale use at the grassroots level.

The COVID-19 testing products, represented by Pluslife Mini Dock, have opened up more scenario possibilities for POCT nucleic acid testing. Pluslife Mini Dock can be applied to scenarios such as customs, airport testing sites, hospital emergencies, rapid preoperative testing, mobile/field labs/testing with the military, community clinics, and even for home self-testing. Through more flexible on-site testing, pandemic prevention and control can be achieved at source. COVID-19 patients can also be detected and quarantined early, while reducing the waiting time for those with negative results.

"With the rapid spread of COVID-19 and increasing need for COVID-19 monitoring, developing suitable nucleic acid Point of Care Testing (POCT) products that are as low-cost and convenient as rapid antigen test, while retaining the accuracy and sensitivity the same as qPCR test, would be meaningful for the society as a whole to better control the pandemic," said Professor Zhou Songyang, founder of Pluslife Biotech.

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