Table 2 The Ct values for EQA samples were determined using various test systems for ORF1ab and N genes at different concentrations

2.0 × 10³

945

32.39 (2.104)

32 (31–34)

18

− 0.6157

3.574

1.0 × 10³

942

33.35 (2.183)

33 (32–35)

18

− 0.932

4.378

5.0 × 10²

939

34.36 (2.021)

34 (33–36)

15

− 0.4432

1.51

2.0 × 10²

752

35.49 (1.979)

36 (34–37)

18

− 0.6895

2.859

2.0 × 10³

938

33.1 (2.179)

33 (32–34)

18

− 0.5439

2.25

1.0 × 10³

936

33.97 (2.241)

34 (33–35)

18

− 0.8828

3.134

5.0 × 10²

939

34.82 (2.112)

35 (34–36)

16

− 0.849

2.656

2.0 × 10²

744

35.86 (1.904)

36 (35–37)

15

− 0.7259

2.336