Dried blood spot sampling offers inexpensive way to widen access to
antibody testing for COVID-19

Date:
October 6, 2020
Source:
University of Birmingham
Summary:
Using dried blood spot samples (DBS) is an accurate alternative to
venous blood in detecting SARS-CoV-2 antibody tests, a new study
has found.



FULL STORY ========================================================================== Using dried blood spot samples (DBS) is an accurate alternative to venous
blood in detecting SARS-CoV-2 antibody tests, a new study by immunology
experts at the University of Birmingham has found.


========================================================================== Currently antibody testing for COVID-19 uses serum or plasma, which
requires a full intravenous blood sample, collected by a trained
phlebotomist. For population-wide or high volume testing, the use of
such sampling is limited by logistic challenges, resources, and costs, as
well as the risk of SARS-CoV- 2 exposure from direct patient contact. In contrast, DBS sampling is simple, inexpensive and can be self-collected
by the patient at home, using a simple finger prick. The sample can then
be collected on a forensic grade card before being posted back to labs
for processing. This offers exciting possibilities to widen access to
antibody testing particularly in more resource limited countries.

Researchers analysed serum and DBS samples from volunteers at University Hospitals Birmingham Foundation NHS Trust, some of whom had previously
tested positive for SARS-CoV-2 by molecular tests, while the status of
other volunteers was either negative or unknown. The anonymised matched
serum and DBS samples were then processed using a highly sensitive
ELISA test, developed by the University's Clinical Immunology Service in partnership with The Binding Site, which specifically detects antibodies
(IgG, IgA and IgM) to the SARS-CoV- 2 trimeric spike protein.

Results showed a significant correlation between matched DBS and serum
samples and minimal differences in results observed by sample type, with negligible discordance. Relative to serum samples, DBS samples achieved
98% sensitivity and 100% specificity for detecting anti-SARS-CoV-2 S glycoprotein antibodies.

100% of the PCR-positive samples were also antibody-positive in DBS.

Senior author Dr Matthew O'Shea from the University's Institute
of Immunology and Immunotherapy said: "Our results have demonstrated
that dry blood spot sampling not only offers a viable alternative for antibodies testing, but one that overcomes the limitations that current
methods can present by eliminating the need for skilled phlebotomists.

"DBS offers the opportunity for wider population-level testing and
improved surveillance in vulnerable groups such as patients with
chronic conditions, the immunocompromised and the elderly by removing
the need to come into contact with a healthcare professional during
sample collection." Co-author Professor Adam Cunningham from the
Institute of Immunology and Immunotherapy said: "As well as offering the opportunity for improved population-wide antibody testing in the UK,
the simplicity and cost- effectiveness of the dry blood spot method
could improve the effectiveness of sampling in low and middle-income
countries, among groups where venepuncture is culturally unacceptable
or in geographically dispersed populations."

========================================================================== Story Source: Materials provided by University_of_Birmingham. Note:
Content may be edited for style and length.


========================================================================== Journal Reference:
1. Gabriella L. Morley, Stephen Taylor, Sian Jossi, Marisol
Perez-Toledo,
Sian E. Faustini, Edith Marcial-Juarez, Adrian M. Shields, Margaret
Goodall, Joel D. Allen, Yasunori Watanabe, Maddy L. Newby, Max
Crispin, Mark T. Drayson, Adam F. Cunningham, Alex G. Richter,
Matthew K. O'Shea.

Sensitive Detection of SARS-CoV-2-Specific Antibodies in Dried
Blood Spot Samples. Emerging Infectious Diseases, 2020; 26 (12)
DOI: 10.3201/ eid2612.203309 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/10/201006091249.htm

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