New smartphone app developed for rapid, sensitive Covid detection

PTI, Jan 31, 2022, 4:43 PM IST

Los Angeles:  US scientists have developed a rapid and sensitive diagnostic system, consisting of a smartphone app and a testing kit, to detect SARS-CoV-2, its variants and the flu virus.

Developed by researchers at the University of California (UC)Santa Barbara, US, the system can provide a platform for inexpensive home-based testing.

It can be readily adapted for other pathogens with pandemic potential including deadly variants of SARS-CoV-2 and flu, they said.

The system, described in the journal JAMA Network Open, succeeded in achieving rapid and accurate diagnosis of COVID-19, SARS-CoV-2 variants, and flu viruses.

The app uses a smartphone’s camera to measure a chemical reaction and determines a diagnosis in 25 minutes, at a fraction of the cost of current diagnostic methods.

”As new COVID variants emerge globally, testing and detection remain essential to pandemic control efforts,” said study lead author Michael Mahan from UC Santa Barbara.

”Nearly half the world’s population has a smartphone, and we believe that this holds exciting potential to provide fair and equal access to precision diagnostic medicine,” Mahan said.

The lab kit can be produced for less than USD 100, and it requires little more than a smartphone, a hot plate and LED lights, the researchers said.

The screening tests can be run for less than USD 7 each versus USD 10 to USD 20 per rapid antigen test and USD 100 to USD 150 per PCR test, they said.

The process, termed smaRT-LAMP, is simple and straightforward.

A small volume of the patient’s saliva is collected and analysed by the smartphone app using the phone’s camera and the diagnostic kit.

No additional specialty materials are required, the researchers said.

PCR tests are the gold standard due to their sensitivity and accuracy, but they are slow, expensive and not portable, they said.

The researchers noted that LAMP tests match the sensitivity and accuracy of PCR — at a fraction of the time and cost.

These tests occurs at constant temperature, which is suitable for point-of-care and home-based testing, they said.

”The key finding was solving the LAMP ‘primer-dimer’ problem — false positives due to high sensitivity — which scientists have struggled with for more than 20 years,” said UC Santa Barbara scientist Douglas Heithoff.

”It took more than 500 attempts to solve it for COVID-19, after which flu viruses were detected on the very first try,” he said.

The simple lab test can detect and differentiate COVID-19 and the flu, which show very similar respiratory disease symptoms and can lead to misdiagnosis.