The Problem with False Positives in COVID-19 Serology Testing

The use of COVID-19 serology tests that produce significant false positives and negatives could have dangerous consequences. Here’s what you need to know about serology tests in the market.
The Problem with False Positives in COVID-19 Serology Testing

In response to the novel coronavirus outbreak, the U.S. Food and Drug Administration has relaxed its rules for development of tests to expedite availability. Companies can now sell antibody tests without submitting their validation data that shows the tests work. However, not all tests are made equal and expediting development has led to some tests actually not working as intended, and others working exactly as intended but still creating false positives or negatives. According to the New York Times, these tests—many made without FDA authorization—can be inaccurate.1

Why high-quality serology tests are a must

The need for high-quality serology tests is going to become even more pressing as many European countries and the U.S. government are contemplating using serology tests to identify people who have a potential immune response to the novel coronavirus and can thus reenter society.

However, the low prevalence of the virus in the general population poses a challenge for tests that do not offer highest sensitivity and specificity. According to 360 Dx, tests without extremely high accuracy could lead to large numbers of incorrect results, resulting in dangerous consequences.2

Key considerations for tests: sensitivity and specificity

Sensitivity and specificity pertain to the accuracy of a test relative to a reference standard. Test sensitivity for novel coronavirus characterizes the test’s ability to detect the SARS-CoV-2 antibodies in patients who do have antibodies; test specificity is the ability of the test to correctly identify those who do not have antibodies.

False positives might lead somebody to believe that they are immune when they are not, and therefore there are significant risks in interpreting the results of these serology tests. 2
Timothy Stenzel
Director, Office of In Vitro Diagnostics and Radiological Health
U.S. Food and Drug Administration

The perils of false positives

To conclude, manufacturers of serology tests need to ensure their tests have very high sensitivity and specificity to mitigate the challenge of low prevalence of infection. Furthermore, manufacturers must use a broad sampling of the population when measuring their serology test’s sensitivity and specificity—not just an ICU population with a high prevalence of infection.


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1 Eder, S., Twohey, M., Mandavalli, A. “Antibody Test, Seen as Key to Reopening Country, Does Not Yet Deliver.” New York Times, Apr 19, 2020. https://www.nytimes.com/2020/04/19/us/coronavirus-antibody-tests.html. Last accessed Apr 20, 2020.

2Bonislawski, A. “False Positives Could Undermine Utility of SARS-CoV-2 Serology Testing.” 360Dx, Apr 16, 2020. https://www.360dx.com/infectious-disease/false-positives-could-undermine-utility-sars-cov-2-serology-testing. Accessed on Apr 20, 2020.

Editorial Team
Editorial Team
The Beckman Coulter editorial team brings you timely news and resources focused on elevating clinical laboratory performance and advancing patient care.

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