Guidelines shed light on serology, antibody testing for COVID-19
In its recent guidance on serology and antibody testing for SARS-CoV-2, the American Association for Clinical Chemistry said that only specific tests should be used and only in certain instances.
However, the organization also stated that these tests could help advance the knowledge base surrounding COVID-19.
Noting the “dubious quality” of many antibody tests on the market, the American Association for Clinical Chemistry (AACC) antibody test guideline stressed that only antibody tests authorized by the FDA or created by a laboratory certified by CMS to create in-house tests should be used for COVID-19 purposes.
“Antibody tests cannot currently determine immunity to COVID-19,” Carmen L. Wiley, PhD, DABCC, AACC president, told Healio Primary Care. “These tests should also not be used to diagnose patients unless they have had COVID-19 symptoms for more than 1 to 2 weeks and tested negative by [polymerase chain reaction (PCR)] tests.”
Wiley explained that antibody tests provide insight into the level of COVID-19 exposure in a community. They can also identify patients who have recovered from the disease and whose blood can be used to help others fight the infection, and potentially aid in the development of a vaccine.
“However, until we know more about COVID-19 prevalence in the U.S., the results of surveillance studies that use antibody testing alone should not be used to make public health policy decisions such as determining COVID-19’s prevalence and relaxing or removing social distancing requirements,” she said.
The AACC explained that COVID-19 serology tests have a “wide range of sensitivity and specificity values.” In its serology testing guidance, the organization recommended that only tests that have received the FDA’s emergency use authorization, or those developed and validated by a laboratory that is certified to perform high-complexity testing, be used to test for SARS-CoV-2.
Serology tests “may be complementary to PCR-based diagnostic testing for management of SARS-CoV-2 infection,” AACC continued. “Serology tests that are performed too early during infection will likely be negative, despite the presence of active infection. Most importantly, it is unclear whether the antibodies produced after infection by SARS-CoV-2 result in lasting protective immunity.”
FDA promises transparency for serology tests
FDA Commissioner Stephen M. Hahn, MD, announced on May 21 that the agency was removing 29 tests from its online list of commercial manufacturers distributing serology test kits for COVID-19, citing the need to “ensure that Americans have access to trustworthy tests.” The kits were removed voluntarily by the manufacturers or by the FDA if the manufacturers did not file an emergency use authorization request or have one pending approval.
The FDA added that the list of tests will continue to be updated. - by Janel Miller and Stephanie Viguers
- AACC.org. AACC issues recommendations on the use of COVID-19 antibody tests. https://www.aacc.org/media/press-release-archive/2020/05-may/aacc-issues-recommendations-on-the-use-of-covid19-antibody-tests. Accessed May 26, 2020.
- AACC.org. AACC recommendations on serological testing. https://www.aacc.org/-/media/Files/Science-and-Practice/Statements/AACC-Statement_Serology-Testing_20200515.pdf?la=en&hash=5933803480BC69877142408739AA6EF438E53E52. Accessed May 26, 2020.