1. Description of studies.
| Participants |
Studies (percentage) (n = 178 studies) |
|
| Sample size1 | Total (no. cases) | 64,688 (25,724) |
| Median sample size (IQR) | 185 (92, 386); range 16 to 5565 |
|
| Median number of SARS‐CoV‐2 cases (IQR) | 94 (47, 168); Range 12 to 1853 |
|
| Continent | Asia | 45 (25) |
| Europe | 94 (53) | |
| North America | 35 (20) | |
| South America | 2 (1) | |
| Australia | 2 (1) | |
| Setting (SARS‐CoV‐2 cases only) | Hospital inpatient | 78 (44) |
| Hospital outpatient | 5 (3) | |
| Emergency departments | 6 (3) | |
| Community | 14 (8) | |
| Quarantine (COVID‐19 suspects) | 1 (1) | |
| Mixed | 35 (20) | |
| Unclear | 39 (22) | |
| Patient group (SARS‐CoV‐2 cases only) | Acute | 45 (25) |
| Acute and asymptomatic | 7 (4) | |
| Acute and convalescent | 77 (43) | |
| Convalescent | 40 (40) | |
| Convalescent and asymptomatic | 3 (2) | |
| Mixed | 6 (3) | |
| Study design | ||
| Recruitment structure | Single group, SARS‐CoV‐2 cases only | 48 (27) |
| Single group, both SARS‐CoV‐2 cases and non‐cases | 5 (3) | |
| Two or more groups, both SARS‐CoV‐2 cases and non‐cases | 124 (70) | |
| Unclear | 1 (1) | |
| Reference standards | ||
| For COVID‐19 cases | All RT‐PCR‐positive | 162 (91) |
| China criteria including RT‐PCR‐negative patients | 7 (4) | |
| Other criteria including RT‐PCR‐negative patients | 4 (2) | |
| Other criteria | 1 (1) | |
| Mixed | 2 (1) | |
| Unclear | 2 (1) | |
| For non‐COVID‐19 cases (n = 180 control groups from 130 studies) | Denominator = 180 | |
| Pre‐pandemic | 81 (45) | |
| Contemporaneous COVID‐19 suspects (RT‐PCR‐negative) | 21 (12) | |
| Contemporaneous healthy or other disease (RT‐PCR‐negative) | 16 (9) | |
| Contemporaneous healthy or other disease (no RT‐PCR reported) | 14 (8) | |
| Cross‐reactivity or confounder panel (any time period) | 31 (17) | |
| Mixed | 17 (9) | |
| Reference standard controls detail for non‐SARS‐CoV‐2 cases | ||
| Pre‐pandemic (n = 81) | Healthy | 27 (34) |
| Healthy and other disease | 50 (63) | |
| Other disease | 1 (1) | |
| Not specified | 2 (3) | |
| Suspected of COVID‐19 (n = 21) | Double PCR‐negative | 6 (29) |
| Single PCR‐negative | 15 (71) | |
| Current RT‐PCR‐negative (n = 16) | Healthy | 3 (19) |
| Healthy and other disease | 2 (13) | |
| Other disease | 9 (56) | |
| Current other disease (RT‐PCR‐negative) | 1 (6) | |
| Not specified | 1 (6) | |
| Current untested (n = 14) | Healthy | 10 (71) |
| Healthy and other disease | 4 (29) | |
| Cross‐reactivity (n = 31) | Pre‐pandemic | 11 (35) |
| Concurrent | 12 (39) | |
| Mixed timing | 4 (13) | |
| Timing not specified | 4 (13) | |
| Mixed (n = 17) | Mixed | 17 (100) |
| Tests | ||
| Number of assays per study (n = 178) | 1 | 76 (43) |
| 2 | 34 (19) | |
| 3 | 32 (18) | |
| 4 | 23 (13) | |
| 5 | 9 (5) | |
| 6 | 6 (3) | |
| 7 | 7 (4) | |
| 8 | 4 (2) | |
| More than 8* | 13 (7) | |
| Test technology (n = 527) | ELISA | 165 (31) |
| CLIA | 167 (32) | |
| LFA | 188 (36) | |
| Other/unclear | 7 (1) | |
| Antigen used (n = 522) | N‐based | 161 (31) |
| S‐based, including | 213 (40) | |
| S1‐based | 89 (17) | |
| RBD | 42 (8) | |
| S‐based (not further specified) | 82 (16) | |
| N‐ and S‐based | 96 (18) | |
| 2019‐nCoV | 3 (1) | |
| Unclear | 54 (10) | |
|
1Based on total number reported per study and does not relate to any particular time slot; the numbers reported in primary studies could be either samples or participants *Number of assays was 10 in 2 studies, 11 in 2 studies, 12 in 2 studies, 13 in 1 study, 14 in 1 study and 16 in 1 study. | ||
Ab: antibody CDC: Center for Disease Control and Prevention CGIA: colloidal gold immunoassay CLIA: chemiluminescence immunoassay ELISA: enzyme‐linked immunosorbent assay FIA: fluorescence immunoassay IQR: interquartile range IIFT: indirect immunofluorescence assay IQR: interquartile ratio LFA: lateral flow assay LIPS: luciferase immunoprecipitation system max: maximum min: minimum N‐based: nucleocapsid protein RBD: receptor binding domain RT‐PCR: reverse transcription polymerase chain reaction S‐based: spike‐protein S‐flow: flow‐cytometry assay WHO: World Health Organization