Table 2 Serological measurements of patients with diagnosis of COVID-19, among qualitative (negative-positive) and semiquantitative (N – Negative; WP – Weak positive; P – Positive) rapid diagnostic test in function of time from the onset of COVID-19 disease and severity of disease, described ad median (IQR)

Negative

Positive

Negative

Weak positive

Positive

Overall

IgM, median (IQR)

0.7 (0.4–1.2)

6.5 (2.1–24.7)

0.7 (0.4–1.2)

2.1 (1.1–4.8)

10.3 (3.3–33.5)

IgG, median (IQR)

1 (0.4–14.7)

75.2 (56.6–93)

1 (0.4–14.7)

53.2 (39.4–74.4)

79.6 (63.8–95.2)

Time from the onset of COVID-19

IgM, median (IQR)

0–15 days

0.7 (0.4–1.1)

4.5 (1.9–9.8)

0.7 (0.4–1.1)

4.1 (1.2–5.1)

5.0 (2.1–36.5)

15–30 days

0.6 (0.3–1.4)

10 (4–34)

0.6 (0.3–1.4)

3.5 (2.8–7.8)

14.2 (6.2–44)

30–60 days

0.6 (0.4–1.1)

7.1 (2.1–28.4)

0.6 (0.4–1.1)

1.7 (1.1-4)

10.7 (2.8–37.7)

> 60 days

0.7 (0.5–1.3)

5.1 (1.6–19.8)

0.7 (0.5–1.3)

1.7 (0.9–4.8)

8.3 (3.3–24.7)

IgG, median (IQR)

0–15 days

0.5 (0.3-1)

75.3 (51-96.4)

0.5 (0.3-1)

51.1 (38.8–85.3)

81.3 (56.7–97.4)

15–30 days

1.45 (0.45–27.7)

75.3 (55-105.3)

1.45 (0.45–27.7)

74.4 (45-105.3)

75.9 (57.1–107)

30–60 days

5.4 (0.5–22.8)

75.1 (58.6–92.7)

5.4 (0.5–22.8)

57.7 (45-70.4)

78.7 (65.5–94.7)

> 60 days

10.8 (1.3–20.6)

75.3 (53.6–91.5)

10.8 (1.3–20.6)

47.0 (28-58.3)

81.5 (64.5–94.4)

Severity of disease

IgM, median (IQR)

Asymptomatic

0.6 (0.4–1.1)

2.8 (1.0-9.7)

0.6 (0.4–1.1)

1.3 (0.7–2.3)

4.2 (1.7–25.8)

Mild

0.7 (0.5–1.3)

4.4 (1.7–13.9)

0.7 (0.5–1.3)

2.1 (1.1–4.6)

7.5 (2.7–22.6)

Moderate-severe

0.6 (0.4–0.7)

21.9 (5.6–66.1)

0.6 (0.4–0.7)

3.8 (1.2–21.5)

23.4 (8.2–68.6)

IgG, median (IQR)

Asymptomatic

0.6 (0.3–5.4)

77.7 (56.5–92.1)

0.6 (0.3–5.4)

56.4 (36.8–74.8)

82.1 (64.1–94.2)

Mild

2.4 (0.5–20.6)

74.9 (55.9–91.3)

2.4 (0.5–20.6)

51.7 (38.3–72.3)

79.4 (65.4–93.2)

Moderate-severe

1.3 (0.4–1.3)

77.3 (58.6–99.9)

1.3 (0.4–1.3)

60.7 (48.6–83.1)

78.4 (59-100.6)