Science is moving at a rapid pace to respond to the novel coronavirus pandemic. In recent months, researchers have developed tests to detect covid-19, the disease caused by the virus, using different substances such as saliva. Now, there’s apparently another substance that can tell us whether someone has covid-19, sputum, commonly known as phlegm.
Researchers at the University of Tehran have developed a test they say is capable of detecting the virus in phlegm. The test uses an electrochemical diagnostic system, also developed by the researchers, to detect reactive oxygen species—unstable molecules that contain oxygen and whose build-up can damage RNA, DNA and proteins and cause cell death—produced by respiratory inflammation. The system is called the ROS Detector in Sputum Sample.
In a recent interview with IEEE Spectrum, Mohammad Abdolahad, an associate professor at the College of Engineering at the University of Tehran, said there are currently no widely available, reliable and fast testing methods for the virus, which he considers a crucial tool for stopping its spread. Results for molecular tests, which are considered highly accurate by the U.S. Food and Drug Administration, can take a day or up to week. Antigen tests, also known as rapid tests, offer results in an hour or less, but are not as accurate. (The FDA says that negative results may need to be confirmed with a molecular test).
Abdolahad led a team of undergraduate and postdoctoral candidates at the university in the development of the test and system.
“Consequently, we have developed a fast method to screen for respiratory inflammation [in] real-time,” Abdolahad told the outlet. “The test can also help inform doctors if the patient has an increased chance of contracting COVID-19. Respiratory diseases can make a patient immunoresistant and by being diagnosed, the patient now knows that she needs to take additional steps in order to protect herself against coronavirus.”
In order to get tested, a person must cough to generate phlegm. While this may sound easy—god knows I’m always hacking it up when I have a cold—it’s more complicated than it seems.
According to the Centers for Disease Control and Prevention, in order to produce a good phlegm sample, you have to first take a few deep breaths while pressing your hand lightly on your stomach. When you cough, the CDC says that you should be inhaling so deeply that you feel it in your stomach. This is almost like practice. Then, you rinse out your mouth with water and spit it out (we don’t want mouth bacteria in the sample). Once you spit, it’s time to put your hand over your stomach and cough again, deeply, into the container provider. Per Abdolahad, in this case the container is a falcon tube.
Each individual tube is tested using a probe with a disposable sensor, made with multi-wall carbon nanotubes, that’s connected to an integrated monitor, he told IEEE Spectrum. The sensor is calibrated according to the presence and severity of covid-19 in patients. The results are displayed on the monitor in 30 seconds.
Calibrating the sensor to correlate with the presence and severity of covid-19 was one of the first challenges the researchers faced, Abdolahad said. To understand the differences between covid-19 and other respiratory diseases, the researchers tested more than 100 people.
“We found that in some respiratory illnesses, such as asthma and acute pneumonia, there is an increase in ROS. Seasonal inﬂuenza on the other hand induces a reduction in ROS levels [in the] immune system and suppresses certain bacterial clearance,” Abdolahad said.
The ROS Detector in Sputum Sample system is being used in four hospitals as a non-invasive, real-time complementary tool for further observational clinical trials, according to IEEE Spectrum. It has received a temporary certificate from the Iranian Food and Drug Administration, which allows the researchers to sell their technology to medical centers. The researchers have also applied for a U.S. patent, but have not received news on their application yet, the outlet reported.