A comparison of SARS-CoV-2 antibody assays evaluated in Auckland, New Zealand.

The aim of the article was to present a comparison of nine SARS-CoV-2 serological assays evaluated in the Auckland region, to determine assay performance in the relevant epidemiological context. Three categories of samples were used: pre-pandemic, pandemic-RT-PCR-negative and pandemic-RT-PCR-positive. Pre-pandemic sera tested on the Abbott, in-house ELISA, cPASS and Euroimmun S1 protein assays were from healthy volunteers and patients with respiratory infections and/or symptoms (n=113). Pre-pandemic sera tested on the Euroimmun N protein, EDI IgG and Roche assays were archived blood bank sera (n=40). Pandemic samples from patients at Auckland City Hospital and Middlemore Hospital, March to May 2020, were tested on all platforms (n=103), with the exception of the Euroimmun N protein and EDI assays on which only Auckland City Hospital samples were tested (n=90). Due to volume constraints, all pandemic samples were not tested on the Abbott assay. This evaluation demonstrates that the IgG, total antibody (IgG plus IgM) and surrogate viral neutralisation assays are broadly comparable with sensitivities between 77.8-100% and specificities of 94.2-100%. In contrast, the IgA and IgM assays demonstrated poor specificity and sensitivity, respectively. This study presents a local evaluation of nine serological assays, with results specific to the epidemiological context of New Zealand. The IgG, the total antibody and surrogate viral neutralisation assays demonstrated high specificity and reasonable sensitivity. The application of these assays needs to incorporate local laboratory workflow and logistics, with respect to anticipated testing volume. These data support deployment of serological assays in New Zealand for testing high-risk groups to assist contact tracing and public health investigations.