Lou 2020 [A].

Study characteristics
Patient Sampling	2‐group study recruiting patients estimating sensitivity and specificity [1] n = 80 confirmed COVID cases [2] n = 300 healthy people enrolled from the community Recruitment: Prospective or retrospective recruitment of cases: Sample size (virus/COVID cases): 380 (80) Inclusion and exclusion criteria: willing to donate blood
Patient characteristics and setting	Setting: inpatient Location: First affiliated hospital of Zhejiang University Country: China Dates: 19 January‐9 February 2020 Symptoms and severity: n = 26. Critical case = any one of a) ARDS or oxygen saturation < 93% and needing mechanical ventilation invasively or non‐invasively; b) shock; c) complication of organ failure requiring ICU support N = 54 non‐critical case (not meeting criteria a) or b) or c) above) Sex: 38.7% female Age: 55 years (IQR 45‐64) Exposure history: for 45/80: incubation period (defined as interval between earliest date of SARS‐Cov‐2 exposure (unambiguous close contact with confirmed COVID‐19 case) and earliest date of symptom onset) range 0‐23 days, median 5 (IQR 2–10)
Index tests	3 tests evaluated, data by time pso reported only for test [A]; tests [B] and [C] were excluded (B] Beijing Wantai ‐ SARS‐CoV‐2 IgG/IgM/Total Ab CGIA; [C] Xiamen InnoDx Biotech SARS‐CoV‐2 CLIA Test name: [A] SARS‐CoV‐2 IgG/IgM/Total Ab ELISA; Manufacturer: [A] Beijing Wantai; [C] Ab targets: Ab; IgM; IgG Antigens used: IgM and Ab: RBD of the SARS‐CoV‐2 S‐protein; IgG: indirect immunoassays using recombinant nucleoprotein of SARS‐CoV‐2 Test method: ELISA, CLIA; LFIA Timing of samples: between 0 and 29 days pso Samples used: serum Test operators: NR Definition of test positivity: NR Blinded to reference standard: unclear Threshold predefined: yes
Target condition and reference standard(s)	Reference standard for cases: confirmed case should meet 3 criteria: 1) fever and/or respiratory symptoms; 2) abnormal lung imaging findings; and 3) positive result of the nucleic acid of SARS‐CoV‐2 Samples used: deep sputum Timing of reference standard: on admission Blinded to index test: unclear Incorporated index test: unclear Reference standard for non‐cases: NR
Flow and timing	Time interval between index and reference tests: NR Results presented by time period: yes All participants received the same reference standard: unclear Missing data: [1] 36, 71 and 58/80 contributed to 0‐7, 8‐14 and 15‐29 days pso estimates of sensitivity for tests [A], [B] and [C] only [2] Not all control group participants were tested by all index tests (range 100‐300/300) Uninterpretable results: NR Indeterminate results: NR Unit of analysis: participant
Comparative
Notes	Funding: China National Mega‐Projects for Infectious Diseases and the Science and Technology Major Project of Xiamen Publication status: preprint Source:Pre‐print server (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?	Unclear
Was a case‐control design avoided?	No
Did the study avoid inappropriate exclusions?	Unclear
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?	No
Were the reference standard results interpreted without knowledge of the results of the index tests?	Unclear
The reference standard does not incorporate the index test	Unclear
Could the reference standard, its conduct, or its interpretation have introduced bias?		High 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?	Unclear
Were all patients included in the analysis?	No
Did all participants receive a reference standard?	Unclear
Were results presented per patient?	Yes
Could the patient flow have introduced bias?		High risk