Table 1 Checkerboard titration of rSARS-CoV-2-N based IgG ELISA

P 1:100

2.953

2.803

2.561

2.182

1.699

N 1:100

0.326

0.318

0.279

0.242

0.204

P/N

9.058

8.814

9.179

9.0165

8.328

P 1:200

2.627

2.411

2.022

1.597

1.34

N 1:200

0.28

0.264

0.259

0.236

0.173

P/N

9.382

9.133

7.807

6.767

7.746

P 1:400

2.095

1.899

1.592

1.051

0.874

N 1:400

0.254

0.196

0.129

0.106

0.04

P/N

8.248

9.689

12.341

9.915

21.85

P 1:800

1.228

1.038

0.797

0.686

0.567

N 1:800

0.215

0.193

0.17

0.084

0.032

P/N

5.712

5.378

4.688

8.167

17.719