Huang 2020.

Study characteristics
Patient Sampling	Purpose: diagnosis of SARS‐CoV‐2 infection (mild COVID‐19 disease); to explore a novel risk score to predict diagnosis with COVID‐19 among all suspected patients at admission Design: retrospective, multicentric observational study Recruitment: retrospective chart review of patients admitted into 26 COVID‐19 designated hospitals in Sichuan Province, China Sample size: n = 475 (336 cases) Inclusion criteria: patients with suspected COVID‐19 (suspected case is defined as having exposure history and 2 clinical manifestations. Patients without epidemiological exposure histories could also be seen as "suspected COVID‐19" only if 3 clinical manifestations were present. Exclusion criteria: none
Patient characteristics and setting	Facility cases: suspected patients with a positive RT‐PCR test Facility controls: suspected patients with a negative RT‐PCR test. If the first test was negative, at least a second test was done, 24 h apart. Country: China Dates: 21 January 2020‐07 February 2020 Symptoms and severity: mild to moderate severity, all suspected patients included Demographics: mean age, cases: 43 years, controls: 34 years. Gender: % female cases 45.8%, controls: 41.0% Exposure history: epidemiological exposure history: cases: 69.6%, controls 12.9%
Index tests	Fever Headache Rhinorrhea Dyspnoea Wheeze Dry cough Haemoptysis Diarrhoea Earache Rash Enlargement of lymph nodes Weakness/fatigue Myalgia Stuffy nose Sore throat Chest pain Productive cough Stomach ache Nausea/vomiting Arthralgia Skin ulcer Unconsciousness
Target condition and reference standard(s)	TC: SARS‐CoV‐2 infection RS: RT‐PCR (if negative, a second test taken at least 24 h apart), sample type not specified
Flow and timing	RS and index tests both taken on admission
Comparative
Notes	Funding: Emergency Response Project for New Coronavirus of Science and Technology Department of Sichuan Provincial, Grant/Award Numbers: 2020YFS0005, 2020YFS0009; Special Funds for COVID‐19 Prevention and Control of West China Hospital of Sichuan University, Grant/Award Number: HX‐ 2019‐nCoV‐068; Science and Technology Benefit People Project of Chengdu Municipality, Grant/Award Number: 2016‐HM02‐00099‐SF
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?	Yes
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?			Low concern
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?	Unclear
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?	Yes
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