“Titer” Tests and Why They Matter

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Photo by Science in HD on Unsplash

We’re all learning a bunch of medical terms we didn’t know (and had no need to know) before. There’s one term which hasn’t come to the forefront yet, but will, and that’s “titer test.”

Most of the people I know who are familiar with the term live in the horse world, for reasons I’ll explain. But we might all end up being intimately familiar with titer tests. Don’t worry. They aren’t that scary.

What is a Titer Test?

There are two other terms that you might also hear: Antibody test and serological immunity test.

Which might make it clearer. A titer test is a test to see if you have antibodies against a disease or infection. (The reason horse people are familiar with them is because there are some horse vaccinations that are really expensive so it’s often cheaper to get a titer test to see if the last one has worn off yet).

Titer tests are most often used to determine whether somebody needs a booster shot or whether a vaccine is working. But they can also tell if you had a disease. This is different from the COVID tests everyone’s fighting to get; those can tell if you have the virus in your system. A titer test can tell if you have COVID, but only about five days or more after you develop symptoms.

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Photo by National Cancer Institute on Unsplash

Why is a Titer Test so Important?

The biggest reason why titer testing is so important during this pandemic is this:

A lot of people who get COVID don’t know they had it. Mass testing in Iceland indicates that as many as 50% of us may catch it and get no symptoms whatsoever. Unfortunately, asymptomatic carriers can still pass the disease to others.

This means that we have a lot of people walking around out there who have already had COVID. Either they got no symptoms or they thought it was a cold, or even seasonal allergies (which are bad this year. Mine have been awful).

This is important for a few reasons:

  1. We almost certainly have healthcare workers who have already had COVID. Note that the rumors of reinfection appear much more likely to be relapses, which is why we’re requiring two negative tests to declare somebody recovered. So, the workers who have already had COVID are, at least temporarily, immune. COVID mutates more slowly than flu strains, so immunity is likely to last at least two to three years. If we could identify who has already had COVID, we can have those people do the procedures with the highest risk of infection.
  2. It’s the only way to trace people who have had COVID and either been asymptomatic or got better, which will give us more accurate epidemiological information.
  3. We are already testing convalescent plasma as a treatment for COVID, and that requires identifying people with good antibodies who can act as donors.
  4. We can test the same people six months apart to get a better idea of how long immunity against COVID lasts, which will be helpful for vaccine development.

Mass titer testing may well be in the future. We already have at least two antibody tests developed, one of which has been approved by the FDA. If we can scale it up, we can start by testing healthcare workers, then move on to other key workers such as grocery store employees. Eventually, the ultimate goal would be to test everyone.

So, What does this Test Involve?

Don’t worry. It’s not too scary. A titer test is a simple blood test; it’s just the same as the cholesterol testing most adults get every year. We’ve all had a blood sample taken at some point.

One of the tests gives results right away, so you might even know before you leave the doctor’s office.

Written by

Freelance writer, freelance editor, novelist and short story writer. Jack of many trades. https://www.jenniferrpovey.com/

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