Table 1.
SARS‐CoV‐2 IgM/IgG detection characteristics by various immunoassays
| Samples | No, (%) |
RDT IgM Positive No (%) |
RDT IgG Positive No (%) |
rIFA IgG Positive No (%) |
ELISA IgG | |||
|---|---|---|---|---|---|---|---|---|
| WB‐EDTA | plasma EDTA | WB‐EDTA | plasma EDTA |
Positive a No (%) |
Ratio Median (IQR) |
|||
| Negative controls | 45 (100) | 0 | 0 | 1 (2) | 1 (2) | 1 (2) | 1 (2) | 0.35 (0.27‐0.43) |
| COVID‐19 patients | ||||||||
| All | 46 (100) | 1 (2) | 5 (11) | 28 (61) | 30 (65) | 31 (67) | 27 (59) | 6.11 (0.40‐11.82) |
| DPD 0‐6 | 20 (44) | 0 | 1 (5) | 6 (30) | 8 (40) | 9 (45) | 6 (30) | 1.51 (0.24‐2.79) |
| DPD 7‐14 | 14 (30) | 0 | 2 (14) | 10 (71) | 10 (71) | 10 (71) | 9 (64) | 6.20 (0.51‐11.89) |
| DPD > 14 | 12 (26) | 1 (8) | 2 (17) | 12 (100) | 12 (100) | 12 (100) | 12 (100) | 12.08 (10.60‐13.55) |
Abbreviations: DPD, days post‐diagnosis; RDT, Augurix rapid diagnostic test; rIFA, recombinant immunofluorescence assays; WB, whole blood.
a
Cut‐offs < 0.5 = negative, ≥0.5 and <1.5 = indeterminate, and ≥1.5 = positive.