I’m not good with blood, particularly my own.
But the instructions and video link for “how to collect your blood sample” for the post-vaccination antibody test made it all seem rather simple: wash hands in warm water, swab ring finger with alcohol pad, “stimulate blood flow” to finger by hanging hand by side and shaking 15 to 20 seconds, place hand palm side up and firmly press lancet into side of finger, puncturing skin.
The “milking” part I had a little more trouble with — the five circles on the collection card each requiring two healthy drops of blood.
Dr. Elaine Chin, founder of the Innovation Health Group, a Toronto-based executive health clinic, offered to send the National Post a complimentary COVID-19 antibodies self-test kit (value: $395) as part of her promotion for her new book, Welcome Back! How to Reboot Your Physical & Mental Health for a Post-Pandemic World, published by Sutherland House Books whose publisher, Kenneth Whyte, is the founding editor of the Post.
In the U.S., demand is growing for antibody tests as people worry about waning immunity. The makers of the blood spot test Chin is offering her patients have screened more than 7,000 blood samples.
The test, Chin said, can help determine the quantity and quality of antibodies the body has produced against SARS-CoV-2.
More specifically, “What we are able to measure with our instrument is useful antibodies that bind tightly to, and stop the interaction between the receptor binding domain” — the part of the virus that first comes into contact with our cells — “and ACE-2,” the receptor in the lungs and other places in the body that allows the virus entry in and that “create the havoc of it all,” explained Hans Frykman, an assistant professor at the University of British Columbia and medical director of Immusafe Inc, which has created and commercialized the test for doctors and their patients.
Toronto-based Vector Health Labs is also offering a commercial antibody test. Vector’s looks whether detectable levels of antibodies are present in the blood — yes or no. “Although it may seem, to some, to not provide enough information, that yes/no, that simple detected/not detected, provides valuable information to the individual,” said Vector’s chief scientific officer Daniel Libertucci.
Frykman’s reports indicate whether the person has low, medium, high or “negative” levels of antibodies, based on the lab’s reference ranges.
But there are lots of caveats: A negative result, the consent form cautioned, doesn’t rule out a previous infection. It also doesn’t mean there was no response from a vaccine. It just may be that the antibodies are no longer detectable, and even then it doesn’t mean immunity is gone. The test doesn’t measure memory B cells that churn out antibodies when the body encounters the infection again. Scientists also still haven’t sorted out how high titers or levels need to be to confer sufficient protection from COVID.
While people might wonder, “Did the vaccine work in me — and is it still working?” the tests, some experts have said, at best offer only a vague idea of someone’s immunity status. Regulators have discouraged their use for “do-it-yourself” immunity check-ins or deciding whether to get boosted, JAMA reported.
“Our position is that when boosters become available to you, in whatever way the province decides to roll out boosters to the masses, you should line up and get it. Period,” said Vector’s Libertucci. “Even if you do have detectable levels of antibody, that is not a reason to refuse the booster.”
Immusafe said its test aims only to be “a guidance to immunity,” and that people with a high blood concentration of antibodies shouldn’t assume there’s no risk of illness, even severe illness, and should continue to follow public health precautions.
“People who do take the test should be conscious that the results might not please them,” Frykman said (my own, five months out from a second shot, were not hugely comforting, but neither were they alarming.) “Lots of people think they’re invincible, and that’s not really the case. We still have to be humble in terms of how immune we are. People need to continue to wear masks and continue to be conscious that the virus is still a real threat.”