TABLE 2.

Specimen groups and the number of specimens per group included in validation of the Ortho NC assay and evaluation of parallel S and NC testing on Roche and Ortho platforms for serosurveillance

Group	Description	no. of specimens
Specificity	Prepandemic blood donor specimens collected prior to 2020 and demonstrated to be anti-SARS-CoV-2 negative by RVP neutralization testing	200
Validation of Ortho NC to replace Roche NC	Preselected Ortho S+/Roche NC- specimens from before vaccines were widely available (July-December 2020)	367
	Preselected Ortho S-/Roche NC+ specimens collected between November 2020 and March 2021	37
	Preselected antigen concordant reactive (Ortho S+/Roche NC+) specimens from before vaccines were widely available (September-December 2020)	190
Evaluation of Parallel S/NC Testing on Ortho and Roche Platforms	Specimens captured through MASS-BD sampling from The Blood Center (New Orleans) for March (n = 1982) and May 2021 (n = 1921)	3903
Durability of Antibody Detection	Longitudinal plasma specimens from 10 convalescent plasma donors	133