Skip to content

The CDC Issued This Grim Warning About Antibody Tests

Viral and antibody testing is critical to opening, but one is far more reliable than the other.
Scientist studies the curves of the Covic-19 pandemic and the dna of an infected person, holding a sample vial in a hospital

The U.S. Center for Disease Control and Prevention revealed that current antibody tests for those who have been infected with COVID-19 are not reliable, casting a cloud over current testing progress so critical to safely reopening a U.S. economy cratered by the coronavirus pandemic.

In guidance posted over the weekend, the CDC noted that if the antibody test is used in a population where the prevalence of COVID-related sickness is low, it's possible that "less than half of those testing positive will truly have antibodies."

There are two sorts of tests that are critical for public health experts to identify the current risks and abatement progress of the COVID-19 contagion. Viral tests determine if one is positive for the coronavirus at the time of testing—and antibody tests—which determine if one's immune system has built antibodies to fight COVID-19. According to the CDC guidance:

In the current pandemic, maximizing specificity and thus positive predictive value in a serologic algorithm is preferred in most instances, since the overall prevalence of antibodies in most populations is likely low. For example, in a population where the prevalence is 5%, a test with 90% sensitivity and 95% specificity will yield a positive predictive value of 49%. In other words, less than half of those testing positive will truly have antibodies. Alternatively, the same test in a population with an antibody prevalence exceeding 52% will yield a positive predictive greater than 95%, meaning that less than one in 20 people testing positive will have a false positive test result.

While both the viral and antibody test results are critical metrics for medical and public health experts to consider, they measure very different things. In the case of antibody tests, the results determine if someone has recovered from COVID-19 or had it and was asymptomatic. It's akin to looking at a "rear-view mirror" of one's health. The antibody testing data is a crucial metric, though the incidence of false-positive results makes it relatively less useful according to the CDC.

More on Coronavirus

  • clean out spices

    This Company's Products Are So Popular It Can't Restock Quickly Enough

    They’re switching all factories to work round-the-clock.
  • This Beloved Fast-Casual Restaurant Chain Was Just Saved from Bankruptcy

    This Beloved Fast-Casual Restaurant Chain Was Just Saved from Bankruptcy

    The coffee and pastries at this cafe could make their return soon!
  • Grocery store bakery cookie display

    Your Local Grocery Store Could Keep This Recent Change For Good

    The food in this section of the store could look a lot different moving forward.
  • Ambulance vehicle parked on a street

    Here Are Your Chances of Catching COVID-19, State by State

  • takeout foods

    The Food Delivery Service That Ships Nationwide

    In case you want a cake from out of state.


Eat This, Not That! is constantly monitoring the latest food news as it relates to COVID-19 in order to keep you healthy, safe, and informed (and answer your most urgent questions). Here are the precautions you should be taking at the grocery store, the foods you should have on hand, the meal delivery services and restaurant chains offering takeout you need to know about, and ways you can help support those in need. We will continue to update these as new information develops. Click here for all of our COVID-19 coverage, and sign up for our newsletter to stay up-to-date.

She Lost 100 Pounds—And Shows You How!

Registered Dietitian and Nutritionist Ilana Muhlstein lost her weight and kept it off—and in You Can Drop It!, she'll show you how to lose it, too. More than 240,000 clients have chosen her program—and now it’s yours to keep.

Filed Under