A Covid-19 test can be tricky like the time when Tesla CEO Elon Musk tested both negative and positive for the virus in one day. They are also quite expensive.

A group of researchers from the University of California, Santa Barbara, however, have conceived a new kind of Covid-testing system that uses an app on your phone and is only a tenth of the price of a PCR test, according to Gizmodo.

The system is called 'smaRT-LAMP' while the app it uses is called Bacticount and the results are said to be as accurate as those from a PCR test.

$7 per sample and 30-minute waiting times

"The virus that causes Covid-19 (SARS-CoV-2) has overlapping symptoms with other respiratory pathogens, such as influenza, which each require different treatment strategies.

"Further, antigen-based testing kits have limited accuracy, and the more reliable PCR nucleic acid tests are expensive and time-consuming. With the Bacticount app and a new nucleic acid testing method, saliva specimens can now be tested for Covid-19 and influenza in about half an hour using a smartphone, for $7 per sample," reads Bacticount's website. 

How does it work?

A patient places some of their saliva into a test kit sitting atop a hot plate. The patient then adds a reactive solution whose role is to amplify viral RNA. The resulting samples are placed into a cardboard box with an LED light stuck to the top. 

That's when the smartphone camera works its magic. It is able to see into the top of the box and identify the colour reactions indicative of whether or not the samples test positive for Covid-19. In the presence of pathogens, the samples will fluoresce with a bright red light. 

A sample size of only 50 patients

The test is still at its very early stages of development. Currently, it is based on a pretty small sample size of only 50 patients which means more research will need to be done to ensure its effectiveness and accuracy. Still, the research team behind it believes it can compete with the PCR tests found today in doctors' offices. 

The researchers also claim it can be modified to tackle other Covid-19 variants and viruses. Could this be the COVID-19 test we have been waiting for? It could but it does have one limitation. It currently only works with Samsung Galaxy S9 smartphones.

If the scientists can make it compatible with other phones, they may have a shot at having the go-to Covid-19 home test. 

The study was published in the journal JAMA Network Open.