Correlation of dried blood spots and plasma for quantification of Immunoglobulin (IgG) against Receptor binding domain and full length spike protein of SARS-CoV-2

We compared plasma and dried blood spots for detection of SARS-CoV-2 IgG antibodies. There was a good correlation between IgG values measured by both sampling methods, r = 0.935 and 0.965 for Receptor Binding Domain and full-length spike protein of SARS-CoV-2. Bland-Altman assessment showed good agreement between two sampling methods. Dried blood spots is a more pragmatic method for collecting samples for sero-epidemiological surveys of SARS-CoV-2 infection.