'Am I protected?': The best way to test for COVID antibodies in Manitoba

Taking a rapid antigen test has become common practice for many Manitobans over the pandemic as they test for COVID-19.

But there is another over-the-counter test Manitobans could use if they are wondering if they have antibodies to the virus. However, one expert says it doesn't give us the whole COVID-19 picture in Manitoba.

The common COVID-19 antibody test uses drops of blood to tell you in minutes if you have an antibody response.

Derek Stein, a scientist at Cadham Provincial Lab, says the test tells if you have IGG antibodies, which are long-lasting, or IGM, which are early antibodies.

He says the tests give you a simple yes or no, which he feels isn't very helpful as it doesn't tell you how many antibodies you have.

"Everyone is going to want to know, 'Am i protected?' That's the question that everyone is asking when they want this antibody test and these antibody tests can't give you the answer to that question right away," said Stein.

Stein runs a more sophistcated test at Cadham testing random blood samples from patients across Manitoba who have had blood taken for various reasons. This is to help determine Manitoba's seroprevalence, meaning the number of persons in a population who test positive for a specific disease. He says it's the best way to tell how many people have had COVID.

"The province is only able to capture the numbers if you go for testing," said Stein. "If you don't go for testing, we don't know whether you've had COVID or whether you've been exposed to COVID, so seroprevalence allows us to capture that whole population."

Stein says the total cumulative rate for COVID-19 antibodies in Manitoba is 82 per cent, meaning 4 out of 5 Manitobans have either been infected by COVID or exposed to it since the beginning of the pandemic.

Antibody responses vary from person to person based on many factors like sex, age or existing medical conditions, according to Stein.

"The response the body makes is really complicated and we are still trying to figure out exactly how all that plays together in terms of immunity and protection," he said.

The tests used at the lab can give answers that the at-home test can't, and that data helps steer public health decisions.

Stein says the largest COVID-19 antibody rate is in those aged 20-39 years old. People 65 and older have lower seroprevalence, which is why booster campaigns target people 50 and older.