July 18, 2020, the U.S. Food and Drug Administration (FDA) issued an emergency use
authorization (EUA) for sample pooling of specimens when using the
SARS-CoV-2 rRT-PCR diagnostic test from Quest Diagnostics. This EUA permits testing up to four samples together in a
batch with a single diagnostic test, also known as sample pooling, which
increases efficiency, given that the majority of COVID-19 test samples
return negative results. This move comes on the heels of FDA’s
June 16 guidance for COVID-19 test developers interested in using pooled samples to preserve
test resources and increase efficiency. It is the first test for which FDA
has granted an EUA to utilize this technique, and will likely lead to
authorization of other tests for similar purposes.
According to FDA, this EUA and the ability to perform sample pooling is
part of government efforts to ensure that larger numbers of COVID-19 tests
are performed more quickly and to conserve test supplies. Increasing
testing for COVID-19 is crucial for ongoing surveillance and detection of
the disease. Pooled samples that return negative results for presence of
the virus likely mean all the patients tested were negative for COVID-19.
However, if there is a positive result, then each of the samples pooled
must be tested individually to identify the positive sample(s). In areas
with low prevalence of COVID-19 where fewer positive results are expected,
sample pooling can assist with surveillance and broad testing in a manner
that may be quicker and more cost-efficient.
FDA’s actions in issuing this EUA demonstrate the desire for continued
expansion of COVID-19 testing as various geographic locales detect and
manage infections. Stakeholders involved in developing COVID-19 tests,
testing patients and processing test samples should carefully review the
EUA, as there may be implications for laboratories, healthcare providers
and others. There may also be some risks in using this technique as there
is a greater likelihood of false negative results if not properly
Laboratory developers of COVID-19 tests seeking to expedite testing by
pooling samples should ensure that they obtain an EUA from FDA for use with
their test, according to FDA’s guidance. Likewise, laboratories interested
in pooling samples should ensure that they use COVID-19 tests authorized by
FDA for sample pooling. Additionally, laboratories may consider focusing
efforts to use sample pooling in geographic areas that are not experiencing
COVID-19 surges, since hot spots would likely have greater numbers of
positive cases and could necessitate more retesting of individual samples.
In addition, hospitals, test sites and other essential businesses that may
need to test significant numbers of individuals should be aware that
certain samples sent to laboratories might be pooled.
Finally, employers and others looking to test on a larger scale as areas of
the country reopen may want to consider pooling samples as a way to screen
employees or large groups for COVID-19 more efficiently. However, these
entities should also remain aware that sample pooling may heighten the risk
of false negatives because of sample dilution. Consequently, where an
individual has a low viral count, the dilution of the individual’s sample
when combined with other samples could result in the testing mechanism
being unable to detect the presence of the virus and lead to a false
negative result. Entities using sample pooling may consider more frequent
testing or other methods to mitigate this risk.
Keeping up with the high demand of COVID-19 testing has proven a challenge
for healthcare centers around the world. Pooled testing may have a
significant impact in reducing testing time, supply usage and resource
McGuireWoods has a dedicated team of experienced lawyers who will continue
to monitor state and federal responses to COVID-19. Please contact the
authors of this alert with any questions and for additional guidance on how
pharmacists and other healthcare professionals are expanding their roles to
diagnose and treat COVID-19. McGuireWoods has published additional thought leadership related to how companies across various
industries can address crucial COVID-19-related business and legal issues.
In a series of video alerts, McGuireWoods’ healthcare lawyers address
issues providers face and overcoming COVID-19 challenges.