Table 2.
Sensitivity performance characteristics of four SARS-CoV-2 IgG antibody immunoassays.
| Days after onset of symptoms | ∑ | TP | FN | EQa | Sensitivity % (95% CI) | PPV % (95% CI) | NPV % (95% CI) | LR+ | LR- | OD |
|---|---|---|---|---|---|---|---|---|---|---|
| Immunoassay | ||||||||||
| ≥ 10 Days | ||||||||||
| Abbottb | 144 | 98 | 46 | - | 68.1 (59.7–75.4) | 100 (95.3–100) | 43.9 (33.1–55.3) | - | 0.31 | - |
| Diasorinc | 146 | 77 | 62 | 7 | 52.7 (44.3–61.0) | 98.7 (92.1–99.9) | 33.0 (23.2–43.1) | 18.5 | 0.49 | 37.9 |
| Euroimmund | 133 | 85 | 46 | 2 | 63.9 (55.1–71.9) | 95.5 (88.3–98.6) | 40.7 (30.1–52.2) | 5.91 | 0.40 | 14.6 |
| Rochee | 145 | 96 | 49 | - | 66.2 (57.8–73.7) | 100 (95.2–100) | 42.4 (31.9–53.5) | - | 0.34 | - |
| ≥ 15 Days | ||||||||||
| Abbott | 52 | 45 | 7 | - | 86.5 (73.6–94.0) | 100 (90.2–100) | 83.7 (68.7–92.7) | - | 0.13 | - |
| Diasorin | 52 | 42 | 8 | 2 | 80.8 (67.0–89.9) | 97.7 (89.2–99.9) | 77.3 (61.8–88.0) | 28.3 | 0.20 | 147 |
| Euroimmun | 49 | 41 | 7 | 1 | 83.7 (69.8–92.2) | 91.1 (77.9–97.1) | 80.5 (64.6–90.6) | 7.74 | 0.18 | 42.3 |
| Roche | 52 | 45 | 7 | - | 86.5 (73.6–94.0) | 100 (90.2–100) | 83.7 (68.7–92.7) | - | 0.13 | - |
| ≥ 20 Days | ||||||||||
| Abbott | 30 | 27 | 3 | - | 90.0 (72.3–97.4) | 100 (84.5–100) | 92.3 (78.0–98.0) | - | 0.10 | - |
| Diasorin | 30 | 26 | 3 | 1 | 86.7 (68.4–95.6) | 96.3 (79.1–99.8) | 89.5 (74.3–96.6) | 30.3 | 0.14 | 221 |
| Euroimmun | 29 | 24 | 4 | 1 | 82.8 (63.5–93.5) | 85.7 (66.4–95.3) | 86.8 (71.1–95.1) | 7.66 | 0.19 | 39.6 |
| Roche | 31 | 28 | 3 | - | 90.3 (73.1–97.5) | 100 (85.0–100) | 92.3 (78.0–98.0) | - | 0.10 | - |
Abbreviations: CI = confidence interval, COI = cut-off index, EQ = equivocal, FN = false negative, LR+ = positive likelihood ratio, LR- = negative likelihood ratio, OD = odds ratio, NPV = negative predictive value, PPV = positive predictive value, ∑ = total number of samples, TP = true positive.
Equivocal sensitivity data were considered false negative in the analyses.
Range FN values 0.01–1.38 and TP values 1.41–9.12 (COI negative result <1.4 and positive result ≥1.4).
Range FN values < 3.80–11.6, EQ values 12.1–14.6, and TP values 15.3–90.7 (cut-off value negative result <12.0 AU/mL, equivocal result ≥12.0 to <15.0 AU/mL, and positive result ≥15.0 AU/mL).
Range FN values 0.14–0.70, EQ values 1.0–1.04, and TP values 1.16– > 13 (COI negative result <0.8, equivocal result ≥0.8 to <1.1, and positive result ≥1.1).
Range FN values 0.06–0.98 and TP values 1.12–88.7 (COI negative result <1.0 and positive result ≥1.0).