Scientists identify test that can diagnose Covid-19 samples in 30 minutes

A new test that can diagnose Covid-19 in just 30 minutes by analysing urine, blood or saliva samples has been identified by scientists.

The method, known as reverse transcription loop-mediated isothermal amplification (RT-LAMP), involves looking for genetic material, or RNA, of the coronavirus in the test samples.

RT-LAMP is a well-known technique that has been previously used to detect viruses such as Zika and Ebola.

Led by Laura Lamb, of Beaumont Health, a healthcare system in Michigan, US, the researchers said the main objective of their study was to look for a rapid screening diagnostic test.

According to the team, the RT-LAMP technique is less expensive, has fewer barriers, and is faster than the standard polymerase chain reaction (PCR) testing method that is currently being used around the world to detect the Sars-Cov-2 virus in patients.

The team conducted tests on simulated patient samples, which involved spiking dummy specimens with genetic material from Sars-CoV-2, as well as clinical samples, which contained the actual Sars-CoV-2 virus.

The samples were tested using RT-LAMP as well as by conventional PCR.

The RT-LAMP method was found to detect Sars-CoV-2 in all the dummy samples in within 30 to 45 minutes.

According to the researchers, the RT-LAMP was positive for 95% (19/20) of these samples and negative for 90% (18/20) of them, when compared with the PCR testing method.

The two samples that were positive by RT-LAMP but negative by the PCR testing could represent false positives, contamination, or increased sensitivity of RT-LAMP compared with PCR, the researchers said.

Commenting on the research, Dr Robert Shorten, chairman of the Microbiology Professional Committee at the Association for Clinical Biochemistry and Laboratory Medicine, said that while the RT-LAMP methodology is faster than conventional methods and uses less equipment, there were limitations to the technology.

He said: “This study shows that the method can detect genetic material from Sars-CoV-2 when this was added to ‘dummy’ samples from volunteers in 19/20 cases.

“However, it also generated 2/20 false positives in negative samples.

“This may be due to cross-reactivity with other viruses or contamination during processing.

“When samples from Covid-19 patients were used (containing actual Sars-CoV-2 virus, rather than purified genetic sequences), it was less sensitive, detecting only 4/10 cases.”

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