Illustration of antibodies (cream), responding to infection with coronavirus (orange). JUAN GAERTNER/SCIENCEPHOTO LIBRARY
The test is quick and inexpensive, taking only 5 minutes. It can determine if you have ever had covid-19 or if you are protected from it by testing for antibodies in your blood or saliva.
The immune system makes antibodies to fight off the coronavirus when a person becomes infected or has been vaccinated. They can be used to detect past infections or vaccine responses. Although tests for coronavirus antibodies exist, they are often expensive, complex, or inaccurate.
Feng Yan from the Hong Kong Polytechnic University, along with his colleagues, developed a more cost-effective and convenient covid-19 test using organic electrochemical transistors. These devices convert biological signals into electrical signals and are increasingly popular for detecting biological molecules such as proteins and glucose.
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One of these transistors is embedded in a small strip of plastic and a drop of saliva or blood is placed on it. The transistor emits electrical signals as coronavirus antibodies attach to it. These signals can be read by a portable Bluetooth meter that is connected to a mobile phone. This entire process takes less that 5 minutes.
When the test was used on blood samples and saliva that had been spiked in different levels of antibody in the laboratory, it proved highly accurate in measuring coronavirus antibodies.
Yan and his colleagues have begun a clinical trial to verify that the test works in real-world environments. Yan says that if the trial proves successful, Yan and his colleagues will apply to be approved to sell the test. The test should cost less than $1 per strip.
Yan says that the new covid-19 antibody test can be used to estimate levels of immunity. It is similar to other tests. He says that it could be used to determine when vaccines' protective effects are beginning to wear off, and if booster shots may need to be given.
The test can't be used to determine if someone is currently infected by covid-19. It usually takes at least a week for antibodies to develop.
Journal reference: Science Advances, DOI: 10.1126/sciadv.abg8387
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