Rapid Blood Test Could Confirm COVID-19 Vaccination in Minutes

Researchers have developed a rapid blood test that can confirm in minutes if a person has been vaccinated for SARS-CoV-2, the virus that causes COVID-19.

The rapid blood test developed by scientists at the Johns Hopkins University (JHU; Baltimore, MD, USA) could confirm a person has been vaccinated while they wait to board a plane or enter a sporting event. Their COVID-19 antibody test is similar to one used at home to determine blood type, where the user pricks a finger and places a drop of blood on a card. A fusion protein developed by the research team is housed on the card and detects COVID-19 antibodies, tiny proteins in the blood the immune system produces to “remember” viral encounters and provide immunity to future infections. Results come back in less than five minutes, faster than current lateral flow tests to detect antibodies at point of care, while also potentially providing a clearer result. Immunocompromised patients, who studies have shown don’t always respond to the COVID-19 vaccine, could test their antibody level and see if the vaccine is working for them, according to the researchers.


The test uses hemagglutination, in which the degree of clumping together of red blood cells reveals the concentration of antibodies. The hemagglutination results could let people know if they still have protection months after they received the vaccine or if they need a booster shot. The degree of hemagglutination also correlated with levels of neutralizing antibodies in patients, which protect against viral infection. In a study on 400 blood samples, half of which were from prior COVID-19 patients, the test correctly identified antibodies in previously infected patients 87.5% of the time, a slightly higher rate than ELISA tests performed in hospitals that require hours to perform. The test could be used to confirm a person’s vaccination instead of having to show a vaccine card, according to Robert Kruse, M.D., Ph.D., who created the blood test.

“If a business is using the honor system for vaccinations, now they could test people on-site,” said Kruse.

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