Table 1.
Serological results obtained using various tests. Positive results are highlighted in grey. NT: not tested due to insufficient quantity. Serum status is identified with two colours in the column of the number of samples: grey, positive; white, negative. The diagnostic accuracy of each test was calculated with the diagnostic test 2 × 2 table according to serum status using MedCalc software (https://www.medcalc.org, version 20.106, accessed on 30 May 2022) (Se: sensitivity; Sp: specificity).
| n.samples | IDScreen SARS-CoV-2N IgGIndirect Multispecies Conjugate | ERADIKIT™ COVID19-Multispecies | Double-Antigen N ELISA IZSLER | Wantai SARS-CoV-2 Ab ELISA | GenScript Surrogate VNT | Proteogenix SARS-CoV-2 Surrogate VNT | VNT (Rijkers et al., 2020) |
|---|---|---|---|---|---|---|---|
| CUT-Off | S/P% ≥ 40 | S/P% ≥ 20 | S/P% ≥ 10 | OD > 1000 | % Inhibition > 30 | % Inhibition | VNT50 ≥ 1/10 |
| 1 | <0.3 | 8.0 | 11.4 | 4549 | 95 | 0 | 1/80 |
| 2 | <0.3 | 100.3 | 40.5 | 4257 | 96 | 0 | 1/80 |
| 3 | <0.3 | 200.7 | 37.2 | 4923 | 96 | 6 | 1/160 |
| 4 | <0.3 | 287.9 | 107.0 | 4584 | 95 | 0 | 1/160 |
| 5 | <0.3 | 155.2 | 73.6 | 4051 | 96 | 0 | 1/160 |
| 6 | <0.3 | NT | NT | 4217 | 95 | NT | 1/160 |
| 7 | <0.3 | 39.7 | 28.1 | 4209 | 96 | 1 | 1/160 |
| 8 | <0.3 | 120.2 | 64.5 | 4157 | 96 | 0 | 1/80 |
| 9 | <0.3 | 190.9 | 61.2 | 3481 | 78 | 0 | 1/80 |
| 10 | <0.3 | 125.3 | 57.4 | 4171 | 95 | 10 | 1/80 |
| 11 | <0.3 | 103.7 | 36.0 | 4305 | 95 | 0 | 1/40 |
| 12 | <0.3 | 247.8 | 64.2 | 4104 | 94 | 23 | 1/160 |
| 13 | <0.3 | 279.3 | 83.5 | 4462 | 95 | 0 | 1/320 |
| 14 | <0.3 | 17.0 | 14.6 | 4310 | 48 | 0 | 1/10 |
| 15 | <0.3 | NT | 114.4 | 4438 | 95 | NT | 1/40 |
| 16 | <0.3 | 167.0 | 49.5 | 4500 | 95 | 0 | 1/80 |
| 17 | <0.3 | 106.5 | 35.9 | 5064 | 96 | 0 | 1/80 |
| 18 | <0.3 | 51.6 | 23.1 | 4416 | 95 | 0 | 1/160 |
| 19 | <0.3 | 108.3 | 38.0 | 4365 | 96 | 0 | 160 |
| 20 | <0.3 | 160.0 | 43.2 | 4247 | 95 | 0 | 1/160 |
| 21 | <0.3 | 17.7 | 2.2 | 4954 | 81 | 0 | 1/40 |
| 22 | <0.3 | 270.5 | 47.1 | 4688 | 78 | 0 | 1/10 |
| 23 | <0.3 | 292.4 | 87.1 | 6068 | 96 | 16 | 1/160 |
| 24 | <0.3 | 194.8 | 69.1 | 4415 | 49 | 0 | 1/10 |
| 25 | <0.3 | 210.6 | 57.2 | 5290 | 96 | 0 | 1/160 |
| 26 | <0.3 | 93.0 | 73.6 | 4512 | 94 | 0 | 1/160 |
| 27 | <0.3 | 39.4 | 73.3 | 5027 | 96 | 0 | 1/80 |
| 28 | <0.3 | 94.0 | 33.8 | 5165 | 94 | 0 | 1/160 |
| 29 | <0.3 | 177.2 | 53.6 | 6016 | 91 | 0 | 1/80 |
| 30 | <0.3 | 178.3 | 44.2 | 4840 | 96 | 0 | 1/80 |
| 31 | <0.3 | 8.8 | 15.1 | 4694 | 94 | 0 | 1/80 |
| 32 | <0.3 | 33.0 | 18.2 | 4472 | 96 | 0 | 1/160 |
| 33 | <0.3 | 14.4 | 0.21 | 4870 | 67 | 0 | 1/10 |
| 34 | <0.3 | 3.1 | 0.2 | 5171 | 95 | 0 | 1/80 |
| 35 | <0.3 | 99.1 | 27.0 | 5171 | 89 | 0 | 1/40 |
| 36 | <0.3 | 137.9 | 50.2 | 4460 | 89 | 0 | 1/160 |
| 37 | <0.3 | 27.4 | 6.12 | 4419 | 44 | 0 | 1/10 |
| 39 | <0.3 | NT | NT | 4875 | 95 | NT | 1/160 |
| 40 | <0.3 | 135.4 | 24.3 | 5419 | 95 | 0 | 1/80 |
| 41 | <0.3 | 1.8 | 12.2 | 6021 | 95 | 3 | 1/160 |
| 42 | <0.3 | 54.5 | 4 | 4817 | 95 | 0 | 1/40 |
| 43 | <0.3 | 238.4 | 96.5 | 5118 | 95 | 0 | 1/80 |
| 45 | <0.3 | 45.7 | 17.4 | 4907 | 96 | 6 | 1/40 |
| 46 | <0.3 | 277.1 | 112.5 | 4845 | 95 | 11 | 1/640 |
| 47 | <0.3 | 13.4 | 0.66 | 6068 | 80 | 0 | 1/40 |
| 48 | <0.3 | 234.1 | 65.3 | 5222 | 94 | 0 | 1/80 |
| 49 | <0.3 | 31.5 | 7.7 | 4892 | 94 | 0 | 1/80 |
| 50 | <0.3 | 38.8 | 17.4 | 4590 | 95 | 17 | 1/320 |
| 51 | <0.3 | 275.4 | 53 | 4687 | 95 | 0 | 1/160 |
| 52 | <0.3 | NT | NT | 4536 | 94 | NT | NT |
| 53 | <0.3 | 158.2 | 63.7 | 4477 | 94 | 0 | 1/80 |
| 54 | <0.3 | 26.8 | 14.8 | 4477 | 95 | 0 | 1/160 |
| 55 | <0.3 | 79.3 | 20.3 | 4521 | 96 | 11 | 1/160 |
| 56 | <0.3 | 164.9 | 90.8 | 4337 | 94 | 0 | 1/160 |
| 57 | <0.3 | 124.7 | 43.6 | 4932 | 95 | 0 | 1/640 |
| 58 | <0.3 | 23.3 | 15.3 | 5601 | 95 | 0 | 1/320 |
| 59 | <0.3 | NT | NT | 4615 | 94 | NT | 1/20 |
| 60 | <0.3 | 36.2 | 20.0 | 4716 | 88 | 0 | 1/40 |
| 61 | <0.3 | NT | NT | 6078 | 95 | NT | NT |
| 62 | <0.3 | 52.2 | 30.0 | 4902 | 95 | 0 | 1/160 |
| 63 | <0.3 | 142.7 | 44.2 | 4692 | 51 | 0 | 1/20 |
| 64 | <0.3 | 228.6 | 91.0 | 4838 | 96 | 0 | 1/160 |
| 65 | <0.3 | 64.1 | 15.1 | 4537 | 88 | 0 | 1/40 |
| 66 | <0.3 | 176.3 | 92.3 | 4509 | 95 | 0 | 1/160 |
| 67 | <0.3 | 26.0 | 19.5 | 4434 | 95 | 0 | 1/160 |
| 68 | <0.3 | 15.9 | 19.2 | 4201 | 94 | 0 | 1/80 |
| 69 | <0.3 | 84.1 | 25.2 | 4652 | 95 | 0 | 1/160 |
| 70 | <0.3 | 123.1 | 50.2 | 4236 | 95 | 0 | 1/160 |
| 71 | <0.3 | 29.5 | 13.5 | 4270 | 89 | 0 | 1/40 |
| 72 | <0.3 | 245.4 | 58.8 | 4115 | 94 | 0 | 1/80 |
| 73 | <0.3 | 115.2 | 86.9 | 3995 | 96 | 0 | 1/160 |
| 74 | <0.3 | NT | NT | 3999 | 89 | NT | 1/40 |
| n.samples | IDScreen SARS-CoV-2N IgGIndirect Multispecies conjugate | ERADIKIT™ COVID19-Multispecies | Double-Antigen N ELISA IZSLER | Wantai SARS-CoV-2 Ab ELISA | GenScript Surrogate VNT | Proteogenix SARS-CoV-2 surrogate VNT | VNT (Rijkers et al., 2020) |
| CUT-off | S/P% ≥ 40 | S/P% ≥ 20 | S/P% ≥ 10 | OD > 1000 | % inhibition > 30 | % inhibition | VNT50 ≥ 1/10 |
| 75 | <0.3 | 11.7 | 4.9 | 98 | 11 | NT | <1/5 |
| 76 | <0.3 | 12.6 | 3.8 | 83 | 0 | NT | <1/5 |
| 77 | <0.3 | 10.0 | 5 | 74 | 9 | NT | <1/5 |
| 78 | <0.3 | 13.8 | 4.6 | 77 | 9 | NT | <1/5 |
| 79 | <0.3 | 13.6 | 3.8 | 35 | 5 | NT | <1/5 |
| 80 | <0.3 | 6.0 | 4.1 | 87 | 0 | NT | <1/5 |
| 81 | <0.3 | 5.8 | 4.5 | 84 | 0 | NT | <1/5 |
| 82 | <0.3 | 6.8 | 4.3 | 159 | 2 | NT | <1/5 |
| 83 | <0.3 | 3.2 | 4.2 | 139 | 4 | NT | <1/5 |
| 84 | <0.3 | 8.6 | 4.5 | 109 | 0 | NT | <1/5 |
| 85 | <0.3 | 10.0 | 4.3 | 135 | 2 | NT | <1/5 |
| 86 | <0.3 | 13.1 | 4.7 | 39 | 5 | NT | <1/5 |
| 87 | <0.3 | 10 | 3.9 | 136 | 3 | NT | <1/5 |
| 88 | <0.3 | 4.2 | 6 | 137 | 5 | NT | <1/5 |
| 89 | <0.3 | 18.7 | 5.6 | 148 | 7 | NT | <1/5 |
| 90 | <0.3 | 8.1 | 5.2 | 216 | 3 | NT | <1/5 |
| 91 | <0.3 | 1.8 | 3.7 | 29 | 0 | NT | <1/5 |
| 92 | <0.3 | 5.5 | 4.2 | 68 | 6 | NT | <1/5 |
| 93 | <0.3 | 3.3 | 4.6 | 84 | 4 | NT | <1/5 |
| 94 | NT | 0.4 | 4 | 20 | 0 | NT | <1/5 |
| 95 | NT | 3 | 4.4 | 113 | 1 | NT | <1/5 |
| 96 | NT | 5.8 | 4.1 | 82 | 0 | NT | <1/5 |
| 97 | NT | 10 | 5.2 | 84 | 0 | NT | <1/5 |
| 98 | NT | 12 | 4.8 | 174 | 4 | NT | <1/5 |
| 99 | NT | 5 | 3.9 | 110 | 0 | NT | <1/5 |
| 100 | NT | 4.5 | 3.7 | 97 | 0 | NT | <1/5 |
| 101 | NT | 10.3 | 3.8 | 97 | 7 | NT | <1/5 |
| 102 | NT | 2.7 | 3.9 | 102 | 1 | NT | <1/5 |
| 103 | NT | 0.1 | 4 | 74 | 0 | NT | <1/5 |
| 104 | NT | 3.6 | 4.1 | 107 | 0 | NT | <1/5 |
| 105 | NT | 4.3 | 4.6 | 73 | 6 | NT | <1/5 |
| 106 | NT | 8.9 | 3.9 | 33 | 10 | NT | <1/5 |
| 107 | NT | 1.9 | 5.3 | 85 | 7 | NT | <1/5 |
| 108 | NT | 10.7 | 4.9 | 127 | 0 | NT | <1/5 |
| 109 | NT | 5.7 | 4.5 | 86 | 3 | NT | <1/5 |
| 110 | NT | 4.6 | 5.2 | 151 | 0 | NT | <1/5 |
| 111 | NT | 3 | 4.3 | 127 | 0 | NT | <1/5 |
| 112 | NT | 2.1 | 4.4 | 17 | 1 | NT | <1/5 |
| 113 | NT | 0.9 | 4.5 | 394 | 1 | NT | <1/5 |
| 114 | NT | 0.0 | 4.3 | 26 | 3 | NT | <1/5 |
| 115 | NT | 0.1 | 5.6 | 532 | 0 | NT | <1/5 |
| 116 | NT | 12.4 | 4.8 | 143 | 2 | NT | <1/5 |
| 117 | NT | 5.0 | 4.2 | 87 | 7 | NT | <1/5 |
| 118 | NT | 4.3 | 4.6 | 68 | 2 | NT | <1/5 |
| Diagnostic test 2×2table | NT | Se: 86.15% (95%CI: 75.34–93.47) Sp: 100% (95%CI: 91.95–100) |
Se: 89.39% (95%CI: 75.36–95.63) Sp: 100% (95%CI: 91.95–100) |
Se: 100% (95%CI: 95–100) Sp: 100% (95%CI: 91.96–100) |
Se: 100% (95%CI: 95–100) Sp: 100% (95%CI: 91.96–100) |
NT | Se: 100% (95%CI: 94.87–100) Sp: 100% (95%CI: 91.96–100) |
| K cohen agreement vs. VNT | NT | K: 0.83 (95%CI: 0.73–0.93) |
K: 0.87 (95%CI: 0.78–0.96) |
K: 1 (95%: +/−0) |
K: 1 (95%: +/−0) |
NT |