Do We Still Need to Test for Covid-19?

Written: April 2022

The public health officials identified clinical laboratories and testing for SARS-CoV-2 coronavirus as central to managing the global outbreaks of the COVID-19 pandemic. Federal funding and clinical laboratory initiatives enabled the development, validation, and implementation of a variety of diagnostic testing alternatives.

At this stage, there are two types of diagnostic tests. The molecular polymerase chain reaction (PCR) test can detect the virus’s genetic material. An antigen test can detect specific proteins on the surface of the virus. Unfortunately, laboratories have experienced multiple challenges, uncertainties, and even controversy as they have attempted to balance the need for increased testing capacity while maintaining high quality laboratory operations.[i]

Consumers have been confused about when they need a test, what kind of test to get, and how to interpret the test results. Some said getting a swab in the back of their nose was unpleasant. False positives and false negatives have raised questions and there has been no abundance of clear explanations.

Researchers at the University of Illinois Chicago (UIC) may have answers. The researchers have designed a high-quality saliva-based analysis which can be used in at-home tests for rapid COVID-19 testing. An early study suggested tests with the new approach may be just as reliable as the PCR tests used by hospitals and laboratories.[ii]

UIC Professor of Pharmacology and Bioengineering Xiaowei Wang said, 

Having fast and easy-to-use tests for COVID-19 is critical, especially in the communities that have low rates of vaccination and low access to health care services, including COVID-19 surveillance and diagnostic testing. The current crisis has created an unprecedented need for rapid tests that are highly sensitive and the sooner we can develop better technology and testing options, the better it will be for everyone.[iii]

The laboratory PCR tests have been most reliable. This is because they follow a highly controlled process, making the tests sensitive and selective. This means the chance of false positives or false negatives is very low. The downside is the tests can be expensive and are not easily accessible in all settings. The at-home and drive by field tests work under less controlled conditions, increasing the chances for false results or inconclusive tests.

The testing method developed by the UIC researchers is called loop-mediated isothermal amplification (LAMP). Wang and the UIC researchers used a computer-based bioinformatics algorithm to identify the best DNA combinations for reliably detecting the virus. The researchers ran a series of computer simulations to determine which analytical steps worked best.

Finally, the team designed experiments to see how the simulated tests performed. They compared the computer-generated artificial samples and human samples with a standard PCR test and their new test. When the results were compared, the researchers found the new LAMP tests were comparable to the more expensive gold standard PCR tests. The LAMP tests were also fast and used saliva instead of the swab thereby making the test inexpensive, comfortable, and easily accessible.

Although the new technique worked, it will need validation through further studies with many samples from real patients. Dr. Wang hopes to conduct a study including 1,500 patient samples by summer. If that goes well, the new approach will be submitted to the U.S. Food and Drug Administration for Emergency Use Authorization.

My reflections – 2022

The pandemic has taken a heavy toll. As of March 30, 3022, there were 483,556,595 confirmed cases of COVID-19, including 6,132,461 deaths, reported to WHO.[iv] Much has been learned about testing, vaccines, and techniques to manage the spread of the disease. Breakthroughs in mRNA vaccine development and potentially the LAMP testing approach will help public health officials around the world to be much better prepared for future outbreaks of new viruses.

[i] Matthew J. Binnicker, “Challenges and Controversies to Testing for Covid-19,”  Journal of Clinical Microbiology (2020), https://journals.asm.org/doi/10.1128/JCM.01695-20

[ii] “New Lamp-Based Assays Rapidly Detect Sars-Cov-2 in Saliva Samples,”  Technology Networks (2022), https://www.technologynetworks.com/diagnostics/news/new-lamp-based-assays-rapidly-detect-sars-cov-2-in-saliva-samples-357130

[iii] Ibid.

[iv] “Who Coronovirus (Coved-19) Dashboard,”  World Health Organization (2022), https://covid19.who.int/?adgroupsurvey={adgroupsurvey}&gclid=CjwKCAjwzaSLBhBJEiwAJSRokq95BqA3q5T5WP3u-jRGW4Wk4kReLR4X0LRGJnCC4wOSe3GLmwX0JBoCatoQAvD_BwE