Peng 2020a.

Study characteristics
Patient Sampling	Purpose: analyse the clinical features and imaging manifestations of COVID‐19 Design: cross‐sectional, single‐centre, retrospective study Recruitment: clinically suspected cases who were sent to hospital for screening Sample size: n = 86 (n = 11) Inclusion criteria: clinically suspected patients Exclusion criteria: not specified
Patient characteristics and setting	Facility cases: positive RT‐PCR via nasopharyngeal swab Facility controls: negative RT‐PCR via nasopharyngeal swab (1x) Country: China Dates: 23 January 2020‐16 February 2020 Symptoms and severity: fever, cough, dyspnoea, sore throat, fatigue, systemic soreness, runny nose Demographics: M/F: total 39/47, cases: 5/6, controls 34/40 Case group: mean age 40.73 ± 11.32 years, 5 men. Control group: mean age 39.67 ± 13.90 years, 34 men Exposure history: 7/11 COVID‐19 patients (63.6%) had a history of travel to Hubei (5 Wuhan, 1 Huanggang, 1 Xiaogan), 2 patients had close contact with the COVID‐19 patients, and 2 taxi drivers
Index tests	Fever Cough Dyspnoea Sore throat Fatigue Systemic soreness Runny nose
Target condition and reference standard(s)	TC: SARS‐Cov‐2 infection RS: RT‐PCR (nasopharyngeal swab)
Flow and timing	Time interval not specified
Comparative
Notes
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?	Yes
Did the study avoid inappropriate exclusions?	Unclear
Did the study avoid inappropriate inclusions?	Unclear
Could the selection of patients have introduced bias?		Unclear risk
Are there concerns that the included patients and setting do not match the review question?			Unclear
DOMAIN 2: Index Test (All tests)
Were the index test results interpreted without knowledge of the results of the reference standard?	Yes
If a threshold was used, was it pre‐specified?	No
Could the conduct or interpretation of the index test have introduced bias?		High 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?	Unclear
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?			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?	Yes
Could the patient flow have introduced bias?		Low risk