Table 1.
Diagnostic accuracy of MSD’s SARS-CoV-2 IgG multiplex assay in COVID-19 patients and healthy controls.
| Cohort | Positive MSD | Negative MSD | Sensitivity % (95% CI) | Specificity % (95% CI) | Positive likelihood Ratio | Negative likelihood Ratio | PPVa % at 5% prevalence | NPVb % at 5% prevalence | |
|---|---|---|---|---|---|---|---|---|---|
| MSD S (cutoff: >869) | |||||||||
| Total (n = 324) | 107/124 | 199/200 | 86.3 (84.8–87.7) | 99.5 (99.3–99.7) | 172.6 | 0.14 | 99 | 92 | |
| PCR Positive (n = 124) | <7 days post PCR + (n = 37) | 21/37 | 16/37 | 56.8 (52.0–61.5) | |||||
| 7–14 days post PCR + (n = 36) | 35/36 | 1/36 | 97.2 (96.0–98.4) | ||||||
| 14 days post PCR + (n = 51) | 51/51 | 0/51 | 100 (98.0–100) | ||||||
| Healthy (n = 100) | 0/100 | 100/100 | 100 (98.0–100) | ||||||
| Other Infections (n = 100) | 1/100 | 99/100 | 99.0 (98.6–99.4) | ||||||
| MSD RBD (cutoff: >592) | |||||||||
| Total (n = 324) | 98/124 | 199/200 | 79.0 (77.2–80.8) | 99.5 (99.3–99.7) | 158.1 | 0.21 | 99 | 88 | |
| PCR Positive (n = 124) | <7 days post PCR + (n = 37) | 15/37 | 22/37 | 40.5 (35.0–46.1) | |||||
| 7–14 days post PCR + (n = 36) | 33/36 | 3/36 | 91.7 (89.6–93.8) | ||||||
| 14 days post PCR + (n = 51) | 50/51 | 1/51 | 98.0 (97.2–98.9) | ||||||
| Healthy (n = 100) | 1/100 | 99/100 | 99.0 (98.6–99.4) | ||||||
| Other Infections (n = 100) | 0/100 | 100/100 | 100 (98.0–100) | ||||||
| MSD N (cutoff: >7225) | |||||||||
| Total (n = 324) | 97/124 | 199/200 | 78.2 (76.4–80.1) | 99.5 (99.3–99.7) | 156.5 | 0.22 | 99 | 88 | |
| PCR Positive (n = 124) | <7 days post PCR + (n = 37) | 14/37 | 23/37 | 37.8 (32.2–43.5) | |||||
| 7–14 days post PCR + (n = 36) | 35/36 | 1/36 | 97.2 (96.0–98.4) | ||||||
| 14 days post PCR + (n = 51) | 48/51 | 3/51 | 94.1 (92.6–95.6) | ||||||
| Healthy (n = 100) | 1/100 | 99/100 | 99.0 (98.6–99.4) | ||||||
| Other Infections (n = 100) | 0/100 | 100/100 | 100 (98.0–100) | ||||||
| MSD NTD (cutoff: >19) | |||||||||
| Total (n = 324) | 97/124 | 199/200 | 78.2 (76.4–80.1) | 99.5 (99.3–99.7) | 156.5 | 0.22 | 99 | 88 | |
| PCR Positive (n = 124) | <7 days post PCR + (n = 37) | 15/37 | 22/37 | 40.5 (35.0–46.1) | |||||
| 7–14 days post PCR + (n = 36) | 32/36 | 4/36 | 88.9 (86.5–91.3) | ||||||
| 14 days post PCR + (n = 51) | 50/51 | 1/51 | 98.0 (97.2–98.9) | ||||||
| Healthy (n = 100) | 0/100 | 100/100 | 100 (98.0–100) | ||||||
| Other Infections (n = 100) | 1/100 | 99/100 | 99.0 (98.6–99.4) | ||||||
a
Positive predictive value, calculated in a presumed 5% prevalence setting.
b
Negative predictive value, calculated in a presumed 5% prevalence setting.