Antibody Test Uses

Serological tests measure the presence of antibodies or proteins in blood when the body is responding to a specific infection, like COVID-19. Typical serology tests detect the body’s immune response to the infection caused by the virus rather than detecting the virus itself. Experts believe that antibodies offer some immunity against COVID-19 re-infection, but so far, scientists do not know enough about immune responses to COVID-19. While some tests only look for an old infection or immunity, others can determine if there is an acute, on-going infection versus an old infection.

Benefits: As a Screening Test

Studies have shown that at least one-third to two-thirds of those infected with COVID-19 are asymptomatic.

By relying only on PCR swab tests and their limited availability, the country may be missing as many as 86% of cases, which may be driving the spread of the epidemic. While swab tests are still the most accurate way to diagnose individuals who are symptomatic in a medical setting, antibody tests are important for understanding epidemic spread in the broader population and to make decisions about congregating for cities, schools, businesses, nursing homes, prisons, churches, and other locations where groups of people work.

If the US had deployed antibody tests in Seattle in early February, they may have shut down the city much sooner. Antibody tests are very useful for cities like Miami or Dallas that have more recent epidemics with many asymptomatic people walking around. By testing everyone in one part of town, one company, or one building, we can have two impacts:

First, it will allow us to quarantine up to 90% of those with asymptomatic infections. This will have tremendous downstream effects, since one person with COVID-19 spreads it to 2-2.5 people on average. For every asymptomatic person we remove from the circulating public, we may stop two new infections and the subsequent two new infections that those people might have caused, and so on. The same phenomenon that causes the virus to propagate quickly means that every case we prevent has a huge impact on limiting the spread.

Second, by utilizing population-wide data from positive serology tests, we can estimate how many people are infected in an area and how many have immunity. This will allow governments, organizations, schools, and businesses to plan how and when to lift and/or restart targeted shutdowns, as active infections decrease and immunity increases.

Benefits: As Proof of Immunity

By specifically targeting our responses to the tide of the epidemic ebbs and flows, we can get more of America back to work safer and sooner. COVID-19 will be a part of our life for the next 12-18 months or longer, until we get a reliable vaccine. In order for those in industries, such as hospitality, tourism, or airlines to be confident that their employees are safe to return to work, or for children to go back to school, we can require immunity testing, which is low-cost, simple, quick and very accurate. For healthcare workers to have peace of mind that they won’t likely get infected again, antibody tests should be required. More importantly, the swab test results can be negative as little as two weeks after active infection, so we won’t know who has already had the infection and is no longer sick. Proof of immunity means that some significant proportion of the population can go back to work immediately without endangering others. Some studies suggest up to 81% of cases are asymptomatic or mild, which means that a great many people are possibly already immune and unaware. We won’t know who those asymptomatic people are until we start deploying antibody tests throughout the country.


It is well documented that antibody tests may miss a portion of sick patients in their early days of infection. Governments, public health practitioners, and doctors who don’t use antibody tests realistically may create more havoc.

In addition, any data we use must be based on reliable tests; not all antibody tests are created equal. In Laredo, Texas, officials discovered the tests they received were found to have a reliability of about 20%.xxviii In March, the Spanish government purchased 64,000 tests from Shenzhen Bioeasy Biotechnology. Anecdotal evidence from Spanish hospitals led to the discovery that the 9,000 tests investigated had a sensitivity of only 30%. The 432-million-Euro order itself had nominally been in compliance with EU standards, but the tests were purchased through a third-party supplier. The company producing the tests did not appear on a list of authorized manufacturers. Elsewhere, in the United Kingdom, the government paid $20 million for 2 million antibody tests from Alltest Biotech and Wondfo Biotech. After Oxford University studies revealed problems with accuracy, the UK government shelved the 2 million antibody tests they had purchased. It is not clear if the tests themselves are faulty or whether they are being used incorrectly as an initial diagnostic for COVID-19, instead of as a screening tool for antibodies.

In conclusion, PCR swab tests and antibody tests both have a place in re-opening American society and keeping it healthier as time progresses. Governments and corporations should be wary of any test without verified scientific results. All those working to re-open America should learn the indications of each type and brand of test and their associated limitations.