High-Throughput Multiplex SARS-CoV-2 IgG Microsphere Immunoassay for Dried Blood Spots: A Public Health Strategy for Enhanced Serosurvey Capacity

Abstract

Testing for antibodies to SARS-CoV-2 has been used to estimate the prevalence of COVID-19 in different populations. Seroprevalence studies, or serosurveys, were especially useful during the early phase of the pandemic when diagnostic testing was not widely available, and the resulting seroprevalence estimates played an important role in public health decision making.

The Serological Sciences Network (SeroNet) for COVID-19: Depth and Breadth of Serology Assays and Plans for Assay Harmonization

“…Eight institutions reported development or use of multiplex or protein arrays for antibody detection ( Table 2 ) ( 27 – 37 ). Sample types include serum, plasma, DBS, saliva, and bronchoalveolar lavage (BAL) fluid.…”

Utility of Newborn Dried Blood Spots to Ascertain Seroprevalence of SARS-CoV-2 Antibodies Among Individuals Giving Birth in New York State, November 2019 to November 2021

“…Magplex-C microspheres (Luminex Corp) were coupled with SARS-CoV-2 Spike subunit S1 (S) (Sino Biological) and nucleocapsid (N) (Native Antigen) antigens. SARS-CoV-2 IgG microsphere immunoassay testing was conducted as previously described, 10 except that Hamilton Microlab Star liquid handling systems were used for DBS elution, microsphere and secondary antibody addition, and incubations. The mean median fluorescence intensity (MFI) of at least 92 SARS-CoV-2 antibody–negative DBS samples was used to set cutoffs for each bead set.…”

“… 3 , 4 Dried blood spot (DBS) testing has been validated for the measurement of SARS-CoV-2 IgG antibodies against N and S proteins. 5 , 6 , 7 , 8 , 9 , 10 Dried blood spots collected by heel stick from infants born in New York State are submitted to the New York State Newborn Screening Program (NSP), where they are tested for more than 50 congenital disorders. Maternal IgG antibodies can pass through the placenta and provide the newborn with passive immunity to infections after birth.…”

“…We analyzed DBS samples collected from 415 293 newborns born in New York State from November 1, 2019, through November 30, 2021, a period that spans the reported arrival of SARS-CoV-2 in the US and the prevaccine and postvaccine phases in New York State. We used a multiplex SARS-CoV-2 microsphere immunoassay that was validated for DBS testing 10 and separately detects IgG antibodies to SARS-CoV-2 N and S antigens. Measuring N and S antibodies independently is useful because both antibodies are known to wane over time, with mean half-lives of 85 days for N and 180 days for S. 15 , 16 In addition, all COVID-19 vaccines currently available in the US produce antibodies to the S antigen only.…”

The Serological Sciences Network (SeroNet) for COVID-19: Depth and Breadth of Serology Assays and Plans for Assay Harmonization

“…Eight institutions reported development or use of multiplex or protein arrays for antibody detection (Table 2). [27][28][29][30][31][32][33][34][35][36][37] Sample types include serum, plasma, DBS, saliva, and bronchoalveolar lavage (BAL) fluid. Diagnostic sensitivity and specificity for multiplex and protein array methods range from 85 -98.8 % and 95.2 -100 %, respectively.…”