Figure 1. Detection of antibodies against SARS-CoV-2 nucleocapsid and spike protein in patients with COVID-19.

Antibody levels against SARS-CoV-2 nucleocapsid and spike protein were determined in 32 pre-2018 blood donors, 10 suspected COVID-19 cases (not PCR confirmed) from EvergreenHealth, Kirkland, WA (EH), three PCR+ COVID-19 patients from UCSD, 13 PCR+ COVID-19 patients from the University of Washington (UW), 13 PCR+ COVID-19 patients from EH, and 6 COVID-19 patients from the NIH Clinical Center (NIH). Each symbol represents a sample from an individual patient or different time points from an individual patient. Antibody levels are plotted in light units (LU) on a log₁₀ scale. Black circles represent plasma or serum samples obtained after 15 or more days after symptom onset and orange circles are from plasma or serum samples obtained 14 or less days after symptom onset. The dashed lines represent the cutoff level for determining positive antibody titers as described in the Methods.