Vialing of NISTmAb primary sample (PS) 8670 and RM 8671 (lots 14HB-D-001, 14HB-D-002, and 14HB-D-003) are described in the first publication of this series . Samples from each RM 8671 lot for homogeneity and value assignment, thaw/freeze (T/F) stability, and accelerated stability analysis were reserved as indicated in the Electronic Supplementary Material (ESM).