Utilizing dried blood spot samples (DBS) is an correct various to venous blood in detecting SARS-CoV-2 antibody checks, a brand new examine by immunology consultants on the College of Birmingham has discovered.
At present antibody testing for COVID-19 makes use of serum or plasma, which requires a full intravenous blood pattern, collected by a educated phlebotomist. For population-wide or excessive quantity testing, the usage of such sampling is restricted by logistic challenges, sources, and prices, in addition to the danger of SARS-CoV-2 publicity from direct affected person contact. In distinction, DBS sampling is straightforward, cheap and could be self-collected by the affected person at residence, utilizing a easy finger prick. The pattern can then be collected on a forensic grade card earlier than being posted again to labs for processing. This provides thrilling prospects to widen entry to antibody testing notably in additional useful resource restricted nations.
Researchers analysed serum and DBS samples from volunteers at College Hospitals Birmingham Basis NHS Belief, a few of whom had beforehand examined optimistic for SARS-CoV-2 by molecular checks, whereas the standing of different volunteers was both detrimental or unknown. The anonymised matched serum and DBS samples have been then processed utilizing a extremely delicate ELISA check, developed by the College’s Medical Immunology Service in partnership with The Binding Website, which particularly detects antibodies (IgG, IgA and IgM) to the SARS-CoV-2 trimeric spike protein.
Outcomes confirmed a major correlation between matched DBS and serum samples and minimal variations in outcomes noticed by pattern kind, 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 have been additionally antibody-positive in DBS.
Senior creator Dr Matthew O’Shea from the College’s Institute of Immunology and Immunotherapy mentioned: “Our outcomes have demonstrated that dry blood spot sampling not solely provides a viable various for antibodies testing, however one which overcomes the constraints that present strategies can current by eliminating the necessity for expert phlebotomists.
“DBS provides the chance for wider population-level testing and improved surveillance in weak teams similar to sufferers with persistent circumstances, the immunocompromised and the aged by eradicating the necessity to come into contact with a healthcare skilled throughout pattern assortment.”
Co-author Professor Adam Cunningham from the Institute of Immunology and Immunotherapy mentioned: “In addition to providing the chance for improved population-wide antibody testing within the UK, the simplicity and cost-effectiveness of the dry blood spot methodology may enhance the effectiveness of sampling in low and middle-income nations, amongst teams the place venepuncture is culturally unacceptable or in geographically dispersed populations.”