Fig. 2: LFA and ELISA values by serological assay.
From: Evaluation of SARS-CoV-2 serology assays reveals a range of test performance
a, LFA scores for each of two readers (blue) and mean ELISA S/CO (purple) for each specimen are grouped by binned time after patient-reported symptom onset and plotted by assay. White cells indicate samples not run with the corresponding assay. For ELISAs, gray indicates S/CO less than or equal to 1. The same legend applies to b and c. The F(ab′)2 specific secondary antibody used in our in-house ELISA preferentially binds the IgG light chain but per the manufacturer has some reactivity for other isotypes (IgM and IgA). b, LFA score and ELISA S/CO values are plotted for pre-COVID-19 historical control serum samples to determine assay specificity. c, LFA score and ELISA S/CO values are plotted for serum samples obtained from 51 individuals after the emergence of COVID-19 (post-COVID-19), some of which received BioFire FilmArray (BioFire Diagnostics) and/or SARS-CoV-2 RT–PCR testing (all negative) as indicated (black cells) in the appropriate columns. Arrows highlight specimens from five individuals with moderate to strong band intensity further discussed in the text. Specimens are grouped by positive testing for coronavirus HKU1 (CoV HKU1), coronavirus OC43 (CoV OC43), influenza A virus A/H3 (FluA H3), influenza A virus A/H1 2009 (FluA H1), parainfluenza type 1 virus (PIV-1), parainfluenza type 4 virus (PIV-4), human metapneumovirus (HMP), adenovirus (ADNV), respiratory syncytial virus (RSV), human rhinovirus/enterovirus (HRE) or negative testing for SARS-CoV-2 and other viruses (nco-).
