Quickly identifying people infected with SARS-CoV-2, the virus that causes COVID-19, is key to fighting the pandemic and preventing future outbreaks.
Currently, the gold standard in testing is the RT-PCR test. However, this test can take some time to show results and is very expensive, especially for low-income countries.
Researchers at the University of Edinburgh may have a solution: an algorithm (or set of rules) for mass testing called the “hypercube” algorithm. This algorithm can test many samples in a single process, reducing screening costs. The algorithm can also detect a positive sample mixed in a batch of negative samples. Using such a model could save a lot of money that could be used in other ways to fight the pandemic.
Testing in Africa
Researchers tested this model in field trials in Africa. Investigators collected swab samples from participants, isolated tiny amounts from those samples, and tested them on other samples. The preliminary results indicated that this method could detect a single positive sample mixed with 99 negative samples.
Not only could this method reduce testing costs, it could also speed up the prosecution of positive cases, benefiting communities and government agencies with limited testing budgets. The model needs further testing in different situations. For example, it is used in Rwanda to screen passengers and in South Africa to regularly screen a rugby team.
“We hope that our method enables regular and inexpensive screening in different contexts. In this way it could help us overcome the Covid-19 pandemic,” said Neil Turok, PhD, member of the team that developed the method , in a press release.
Different types of bulk tests for COVID-19 are checked for safety and performance. The US Food and Drug Administration (FDA) has promoted the development of an effective, large-scale tool for screening people.
Pooled Sample Testing is an example of mass testing. The process involves mixing multiple samples in one batch, which is then tested. If the lot tests negative, all samples are considered negative. This method saves resources.
However, there is a disadvantage: pooled tests use diluted whole samples, which can affect the detection rate. According to the FDA, pooled tests can contain more false negative results. This may work in areas with low cases of COVID-19 where more negative results are expected, but can be a problem in areas with high numbers of cases. The FDA recommends that pooled tests match at least 85% positive of individual tests.
Why it matters
Due to COVID-19, resources are scarce in various regions. Even if individual tests can be done quickly, having a person tested more than once is costly. Mass testing can save money for governments, private businesses, and households. It can also prevent frequent and costly lockdowns in communities. In one fell swoop, an entire community can be tested for COVID-19, isolating all of those who test positive to prevent an outbreak. The decrease in citywide lockdowns allows people to take up their jobs and earn an income while enduring the pandemic.
Ralph Chen is an enthusiast for medical topics and advanced technology. When he’s not writing, he spends a lot of time playing popular PC games.