Li 2020 [A].

Study characteristics
Patient Sampling	Purpose: Diagnosis of acute‐phase infections Design: Single‐group study estimating sensitivity alone: 49 NAT‐confirmed 2019‐nCoV infected patients (hospitalised patients) Recruitment: Not stated Prospective or retrospective: Not stated Sample size: 49 (49) Further detail: no more details available
Patient characteristics and setting	Setting: hospitalised patients Location: The Fifth Medical Centre of PLA General Hospital of China Country: China Dates: December 2019 to February 2020 Symptoms and severity: 12 (24%) severe; 37 (76%) mild illness; fever (41/49), cough (26/49), fatigue (11/49), dyspnoea (6/49), diarrhoea symptom (0/49); 17 had other systematic diseases (8 hypertension, 5 diabetes, 2 asthma, 1 AIDS, 1 tuberculosis, 1 hepatitis) Demographics: 30, 61% male; median age 43y (IQR: 3 to 79y) Exposure history: 35 patients had been to Wuhan before illness onset or lived in Wuhan city, others had never been to Wuhan recently. Non‐Covid group 1: NA
Index tests	Test name: [A] SP‐based IgG/IgM ELISA; [B] N‐protein based IgG/IgM ELISA Manufacturer: [A] Hotgen Biotech (Beijing, China); [B] Livzon Group (Guangdong, China) Antigen target: [A] S (Spike); [B] N (Nucleocapsid) protein. Evaluation setting: Laboratory Test method: ELISA Timing of samples: Day 2 to 45 pso; 40 samples collected at < 10 days; up to 41 samples > 10 days Samples used: serum Test operator: not reported Definition of test positivity: the S/CO values ≥ 1 considered positive results, < 1 negative Blinding reported: Unclear Threshold predefined: not reported
Target condition and reference standard(s)	Reference standard: NAT; no further details Samples used: not reported Timing of reference standard: Not reported Blinded to index test: yes, reference standard done before index test Incorporated index test: no Definition of non‐COVID cases: NA Samples used: Timing of reference standard: Blinded to index test: Incorporated index test:
Flow and timing	Time interval between index and reference tests: not reported All patients received same reference standard: Yes; all NAT‐tested Missing data: none reported Uninterpretable results: none reported Indeterminate results: none reported Unit of analysis: 206 serum samples from 49 patients
Comparative
Notes	Funding: This work was supported by the Emergency Project for 2019‐nCoV of PLA General Hospital (20EP013). Publication status: Pre‐print Source: Lancet Infectious Diseases Author COI: authors reported no conflict of interest.
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?	Unclear
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?	Unclear
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	Yes
Could the reference standard, its conduct, or its interpretation have introduced bias?		Unclear risk
Are there concerns that the target condition as defined by the reference standard does not match the question?			Low concern
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?	Yes
Were all patients included in the analysis?	Unclear
Did all participants receive a reference standard?	Yes
Were results presented per patient?	Yes
Could the patient flow have introduced bias?		Unclear risk