Table 1.
Characteristics of the included studies
| Study Count | Author Name | Country | Median Age in Years | Gender Distribution | Study Design | Patient Included | Sample Size | Time of Sample Collection | Type of N-antigen Test | Comparator Test | Manufacturer's Cutoff | Sensitivity (at Manufacturer's Cutoff) | Specificity (at Manufacturer's Cutoff) | Sensitivity (0–7 Days) | Sensitivity (8–14 Days) |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1 | Zhang et al | United States of America | 48 | 67% M, 33% F | Cohort | Hospitalized + outpatient | Not reported | Days from symptom onset | SARS-CoV-2 Ag quantitative assay kit (Biohit Healthcare) | RT-PCR | 2.97 | 81.5% | 98.3% (91.1–99.9) | 90.9% (85.1–94.6) | Not reported |
| 2 | Yokoyama et al | Japan | Not reported | Not reported | Case-control | Hospitalized | 487 | Days from symptom onset | iFlash-2019-nCoV Antigen kits and an iFlash3000 fully automated CLIA analyzer (sandwich complex): (Shenzhen, China) | RT-PCR | 1 cutoff Index | 84.8% | 99.0% | Not reported | Not reported |
| 3 | Wang et al | United States of America | 56 | 47% M, 53% F | Case-control | Hospitalized + outpatient | Not reported | Days from symptom onset | S-PLEX SARS-CoV-2 N Kit (Meso ScaleDiagnostics) | RT-PCR | 2.80 log 10 fg/ml | 91.9% ( 83.2–97) | 94.2% (84.1–98.8) | 89.8% (77.8–96.6) | 91.4% (82.3–96.8) |
| 4 | Thudium et al | Denmark | Not reported | 38% M, 62% F | Cohort | Hospitalized + outpatient | 914 | Days from RT-PCR positive | SARS-CoV-2 Antigen ELISA kit (Solsten Diagnostics International, Aarhus, Denmark) | RT-PCR | 10 | 82.8% (73–92.5) | 99.8% (99.4–100) | 92.9% (87.9–98.0) | 91.6% (87.1–96.2) |
| 5 | Sigal et al | United States of America | 12.9 | 56% M, 44% F | Case-Control | Hospitalized | 36 | Days from Hospitalisation | MSD S-PLEX CoV-2 N assay kits (Meso Scale Discovery, Rockville, MD | RT-PCR | 1.28 | 89% (75–96) | 95% (85–99) | Not reported | Not reported |
| 6 | Shan et al | Germany | Not reported | Not reported | Case-Control | Hospitalized | 135 | Days from Hospitalisation | SIMOA technology | RT-PCR | 1.25 | 97.5% | 100% | Not reported | Not reported |
| 7 | Li et al | China | Not reported | Not reported | Case-Control | Hospitalized | SARS-COV-2 RT-PCR+, ab neg: 50 samples SARS-COV-2 RT-PCR+, ab pos: 37 samples |
Days from Hospitalisation | ELISA | RT-PCR | 10 | 76.8% | 100% | Not reported | Not reported |
| 8 | Hingrat et al | France | Not reported | Not reported | Case-Control | Hospitalized | SARS-COV-2 RT-PCR−: 63 samples SARS-COV-2 RT-PCR+: 227 samples |
Days from symptom onset | E-IVD ELISA microplate assay, COVID-Quantigene¬Æ(AAZ) | RT-PCR | … | 79.3% (74–84.6) | 98.4% (95.3–100) | <14 days: 93% (88.7–97.2) | Not reported |
| 9 | Deng et al | China | Not reported | 52% M, 48% F | Case-Control | Hospitalized | 914 | Days from symptom onset | Chemiluminescence immunoassay by iFlash immunoassay analyzer (Shenzhen Yhlo Biotech Co., Ltd,Shenzhen, China) | RT-PCR | 1.46 | Not reported | 98.8% | 76.3% | 62.5% |
| 10 | Ahava et al | Finland | Panel A: 54, Panel B: 50, Negative Panel: 53 | 41% M, 59% F | Cohort | Unclear | 281 | Days from symptom onset | Salocor N-antigen ELISA (Salofa) | RT-PCR | 2.97 | 91.7% (73–99). | 98% (94.2–99.6). | 96.2% (80.4–99.9) | 91.7% (73–99) |
| 11 | Favresse et al | Germany | 78 | 51% M, 49% F | Cohort | Hospitalized + outpatient | 243 | Days from symptom onset | SIMOA technology + iFlash-2019-nCoV Antigen kits | RT-PCR | Simoa: Unknown; iFlash: >1.0COI | Between day 2–14 in severe patients: Simoa: Sens: 84.6% (57.8–97.3), global sensitivity: 96.9%; IFlash: Sens:76.9% (49.7–91.8). global sensitivity: 96.2% | Between day 2–14 in severe patients: Simoa : 97.2% (90.3–99.5); iFlash: 93.0% (84.6–97.0) | <10 days—Simoa: Severe—100%. Non severe—91.3% (<3 d) to 100% (4 to 10 d); iFlash: Severe—100%. Non severe-93.5% (<3 d) to 96% (4 to 10 d) | 11–20 days—Simoa: severe—88.5%, Non severe: 86.5%; iFlash: severe—80.8%, Non severe—86.5% |
| 12 | Gwyn et al | United States of America & Nigeria | Not reported | Not reported | Cohort | Unclear | 416 | Days from symptom onset | Monoplex and Multiplex testing on MAGPIX and Bioplex | RT-PCR | MAGPIX = 1046, Bio-Plex = 3683 | MAGPIX: Multiplex—96.5% (90.3–99.3); Monoplex- 95.4% (88.6–98.7). Bio-Plex: Multiplex—96.5% (90.3–99.3); Monoplex—96.6% (90.3–99.3) | MAGPIX: Multiplex—98.3 (94.0–99.8); Monoplex—99.2 (95.3–100). Bio-Plex: Multiplex—97.4% (90.3–99.3); Monoplex—98.3 (93.4–100) | Not reported | Not reported |
| 13 | Mathur et al | United States of America | Not reported | 45% M, 55% F | Cohort | Outpatient | 297 | Days from symptom onset | SIMOA technology | RT-PCR | 1.25 | Global Sensitivity not reported | Global Specificity not reported | Sensitivity —Infection-77.6% (64–88.2) Infectious viral shedding: 100%(88.4–100). Specificity—Infection: 100%(84.6–100); Infectious viral shedding—65% (40.8–84.6). | Sensitivity—Infections—43.2(31.1–54.5) infectious viral shedding 70%. Specificity: Infections: 100% (84.6–100), Infectious viral shedding: 64.3% |
| 14 | Oueslati et al | France | Not reported | Not reported | Cohort | Unclear | 289 | Days from symptom onset | COVID-VIRO-LFIA and COV-QUANTO-ELISA (AAZ, Boulogne-Billancourt, France) | RT-PCR | 2.98 | LFIA : Infection: 59% (45–71.6); Infectiousness: 76% (59.4–88). ELISA: Infection—66% (52–77.8) ; Infectiousness : 87% (71.1–95.1) | LFIA: 100% (92–100) | Not reported | Not reported |
| 15 | Verkerke et al | United States of America | Not reported | Not reported | Cohort | Hospitalized + outpatient | 1860 | Days from testing and symptoms | SIMOA technology | RT-PCR | Unclear | 85.80% | 98.60% | Not reported | Not reported |
| 16 | Hiling et al | Denmark | Not reported | Not reported | Cohort | Unclear | 272 | Unclear | SIMOA technology, Solsten ELISA and Elecsys ECLIA | No single comparator test (pairwise comparison between 3 assays) | Solsten ELISA—10 ng/L, SIMOA—0.15 ng/L and Elecsys ECLIA—no cutoff for plasma (used assay linearlity with and without extraction buffer in 10 positive and 10 negative matched heparin and EDTA samples) | SIMOA versus Solsten—For both Tests: 87.8% (81.3–92.6), SIMOA versus Elecsys ECLIA—SIMOA: 75.5% (67.7–82.2); ECLIA: 100% (96.7–100), Solsten ELISA versus Elecsys ECLIA—ELISA: 74.8%(67–81.6); ECLIA 99.1% (95.1–100) | SIMOA versus Solsten—For both Tests: 85.6% (78.2–91.2), SIMOA versus Elecsys ECLIA—SIMOA: 100% (97.1–100); ECLIA: 77.6% (70.4–83.8), Solsten ELISA versus Elecsys ECLIA—ELISA: 99.2%(95.6-100); ECLIA 77% (69.7–83.3) | Not reported | Not reported |
Abbreviations: Ab, antibody; CI, confidence interval; CLIA, chemiluminescence assay; ELISA, enzyme-linked immunosorbent assay; LFIA, lateral flow immunoassay; N, nucleocapsid; NR, not reported; RT-PCR, reverse-transcriptase polymerase chain reaction; SARS-Cov-2, severe acute respiratory syndrome coronavirus 2. MFI-bg, median fluorescence intensity minus background.