Fig. 3.

Comparison of DBS vs. serum collection on serostatus determination for specimens tested 7 days after collection. A. Serum OD ratios highlighting discordant qualitative results when measured using DBS. B. DBS OD ratios highlighting discordant qualitative results when measured using serum. C. DBS OD ratio for OD ratios ≤ 1.3. Orange and blue dots represent discordant qualitative results between serum and DBS. All other data points are concordant between the two cohorts. Red lines indicate the assay's analytical decision points (0.8, 1.1). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)