Lassauniere 2020 [A].

Study characteristics
Patient Sampling	2‐group design estimating sensitivity and specificity for 9 tests Groups: [1] COVID‐19‐positive group (n = 30) admitted to ICU; [2] non‐COVID‐19 group (n = 82) including pre‐pandemic (2017) blood donors (n = 10); acute viral respiratory tract infections with other coronaviruses (n = 5) or non‐coronaviruses (n = 45); dengue virus (n = 9), CMV; n = 2 and Epstein Barr virus (n = 10). 1 additional patient positive for both CMV and Epstein Barr virus. Recruitment: [1] recruited consecutively (all cases in ICU on a single day); [2] unclear Sample size (virus/COVID cases): 112 (30) Inclusion and exclusion criteria: none stated
Patient characteristics and setting	Setting: [1] ICU; [2] biobank samples Location: [1] Hillerød Hospital Country: Denmark Dates: NR Symptoms and severity: NR Sex: 75% (24/32) male Age: median 67 years (IQR 52‐76) Exposure history: NR
Index tests	9 tests evaluated, 3 ELISA and 6 LFIA; this entry ( Lassauniere 2020 [A] ), refers to test [A] in the list below: [A] test name: Wantai SARS‐CoV‐2 Ab ELISA Manufacturer: Beijing Wantai Biological Pharmacy Enterprise, Beijing, China; Cat # WS‐1096 Ab targets: total Ab Antigens used: SARS‐CoV‐2 S‐protein RBD Test method: ELISA Timing of samples: not reported Samples used: serum Test operators: laboratory staff Definition of test positivity: calculated negative control value to 0.160 Blinded to reference standard: no Threshold predefined: yes [B] test name: Anti‐SARS‐CoV‐2 IgG ELISA Manufacturer: Euroimmun Medizinische Labordiagnostika, Lübeck, Germany; Cat # EI 2668‐9601 G Ab targets: IgG Antigens used: SARS‐CoV‐2 S‐protein subunit 1 (S1) Test method: ELISA Timing of samples: not reported Samples used: serum Test operators: laboratory staff Definition of test positivity: ratio < 0.8 was considered negative, ≥ 0.8 and < 1.1 borderline, and ≥ 1.1 positive. For analysis 1.1, a more stringent cut‐off was used, and all values < 1.1 were considered negative. Blinded to reference standard: no Threshold predefined: yes [C] test name: Anti‐SARS‐CoV‐2 IgA ELISA Manufacturer: Euroimmun Medizinische Labordiagnostika, Lübeck, Germany; Cat # EI 2606‐9601 A Ab targets: IgA Antigens used: SARS‐CoV‐2 S‐protein subunit 1 (S1) Test method: ELISA Timing of samples: not reported Samples used: serum Test operators: laboratory staff Definition of test positivity: ratio < 0.8 was considered negative, ≥ 0.8 and < 1.1 borderline, and ≥ 1.1 positive. For analysis 1.1, a more stringent cut‐off was used, and all values < 1.1 were considered negative. Blinded to reference standard: no Threshold predefined: yes [D] Test name: 2019‐nCOV IgG/IgM Rapid Test Manufacturer: Dynamiker Biotechnology, Tianjin, China Cat # DNK‐1419‐1 Ab targets: IgM, IgG Antigens used: NR Test method: CGIA Timing of samples: not reported Samples used: serum Test operators: laboratory staff Definition of test positivity: visible line Blinded to reference standard: no Threshold predefined: yes [E] Test name: OnSiteTM COVID‐19 IgG/IgM Rapid Test Manufacturer: CTK Biotech, Poway, CA, USA; Cat # R0180C Ab targets: IgM, IgG Antigens used: NR Test method: CGIA Timing of samples: Samples used: serum Test operators: laboratory staff Definition of test positivity: visible line Blinded to reference standard: no Threshold predefined: yes [F] Test name: Anti‐SARS‐CoV‐2 Rapid Test Manufacturer: AutoBio Diagnostics, Zhengzhou, China; Cat # RTA0204 Ab targets: IgM, IgG Antigens used: NR Test method: CGIA Timing of samples: not reported Samples used: serum Test operators: laboratory staff Definition of test positivity: visible line Blinded to reference standard: no Threshold predefined: yes [G] Test name: Coronavirus Diseases 2019 (COVID‐19) IgM/IgG Ab Test Manufacturer: Artron Laboratories, Burnaby, Canada; Cat # A03‐51‐322 Ab targets: IgM, IgG Antigens used: NR Test method: CGIA Timing of samples: not reported Samples used: serum Test operators: laboratory staff Definition of test positivity: visible line Blinded to reference standard: no Threshold predefined: yes Insufficient samples available to report data by time pso for tests [H] and [I], therefore excluded from this iteration of the review [H] Test name: 2019‐nCoV IgG/IgM Rapid Test Cassette Manufacturer: Acro Biotech, Rancho Cucamonga, CA, USA; Cat # INCP‐402 Ab targets: IgM, IgG Antigens used: NR Test method: CGIA Timing of samples: Samples used: serum Test operators: laboratory staff Definition of test positivity: visible line Blinded to reference standard: no Threshold predefined: yes [I] Test name: 2019‐nCoV IgG/IgM Rapid Test Cassette Manufacturer: Hangzhou Alltest Biotech, Hangzhou, China; Cat # INCP‐402 Ab targets: IgM, IgG Antigens used: NR Test method: CGIA Timing of samples: not reported Samples used: serum Test operators: laboratory staff Definition of test positivity: visible line Blinded to reference standard: no Threshold predefined: yes
Target condition and reference standard(s)	Reference standard for cases (including threshold): viral nucleic acid detection (no further detail) in hospital patients Samples used: respiratory Timing of reference standard: during hospital stay Blinded to index test: yes Incorporated index test: no Reference standard for non‐cases: pre‐pandemic (2017)
Flow and timing	Time interval between index and reference tests: unclear Results presented by time period: days since onset: 7‐13 (n = 7); 14‐20 (n = 15); ≥ 21 (n = 8) All participants received the same reference standard: no Missing data: some participant samples were not tested with all assays. Only 32 of the 80 control participants were tested with POC assays. Unclear how the 32 were selected Uninterpretable results: not mentioned Indeterminate results: borderline results for [2] and [3] were considered test‐negative. For POC tests, weak signals for IgM and IgG were considered positive. Unit of analysis: participants
Comparative
Notes	Funding: Danish National Biobank resource, supported by the Novo Nordisk Foundation Publication status: preprint (not peer reviewed) Source: medRxiv Study author COI: none declared
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	Yes
Was a case‐control design avoided?	No
Did the study avoid inappropriate exclusions?	Yes
Did the study avoid inappropriate inclusions?	No
Could the selection of patients have introduced bias?		High risk
Are there concerns that the included patients and setting do not match the review question?			High
DOMAIN 2: Index Test (All tests)
DOMAIN 2: Index Test (Antibody tests)
Were the index test results interpreted without knowledge of the results of the reference standard?	Unclear
If a threshold was used, was it pre‐specified?	Yes
Could the conduct or interpretation of the index test have introduced bias?		Unclear risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
The reference standard does not incorporate the index test	Yes
Could the reference standard, its conduct, or its interpretation have introduced bias?		Low risk
Are there concerns that the target condition as defined by the reference standard does not match the question?			High
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Unclear
Did all patients receive the same reference standard?	No
Were all patients included in the analysis?	No
Did all participants receive a reference standard?	Yes
Were results presented per patient?	Yes
Could the patient flow have introduced bias?		High risk