This usually involves a test using a technique called immunochromatography that can determine whether antibodies have been produced, but it’s not the best technique nor the most precise, and testing can take several days or even a week.
This is a problem that Yoshihiro Ito from RIKEN CEMS, whose team have since produced a rapid antibodies testing kit that can return results in as little as 30 minutes. This tech was actually developed by Ito several years ago that can immobilize organic compounds that can help measure the history of immune infection.
Over the years, the tech has been improved upon and has since expanded to cover more than 40 different allergens, and now also covers several key COVID-19 proteins. How it works is that a microchip is coated with a substance that can react to light. A sample liquid containing the protein of interest is dropped onto the microchip and then exposed to ultraviolet light that immobilizes the protein.
A CCD camera is then used to measure the amount of emitted light which happens when antibodies in the blood serum bind to the viral proteins, and from there, the system can then quantify the number of antibodies present.
According to Ito, “Standard quantitative analysis of antibodies usually requires a half milliliter of blood drawn from one of your arms, which is a lot! But in our system, all that is needed is a small drop of blood from the fingertip, and the sensitivity of the system is 500 times higher than that of conventional immunochromatography, meaning that detection is possible even when the number of antibodies is very low.”