Tolia 2020.

Study characteristics
Patient Sampling	Purpose: diagnosis of acute SARS‐CoV‐2 infection Design: cross‐sectional, retrospective study Recruitment: all patients presenting to 1 of 2 EDs, located at an urban teaching hospital, and academic quaternary medical centre, within the same healthcare system who had targeted testing based on clinician's decision during the initial 10 days of test availability Sample size: n = 283 (29 cases) Inclusion criteria: patients presenting with symptoms related to COVID‐19 infection (fever and cough or shortness of breath) travel within 14 days to countries with high rates of infection (at that time China, Iran, Italy, Japan, and South Korea) or risk factors for infection complications (including age or comorbid conditions) or the patient was a healthcare worker who could potentially expose others at risk and clinician made decision for testing Exclusion criteria: not specified
Patient characteristics and setting	Facility cases: positive SARS‐CoV‐2 test Facility controls: negative SARS‐CoV‐2 test, visiting the same EDs and being tested Country: USA (San Diego, CA) Dates: 10 March 2020‐19 March 2020 Symptoms and severity: all patients presenting to ED who were eligible for targeted testing (= patients presenting with symptoms related to COVID‐19 infection (fever and cough or shortness of breath) travel within 14 days to countries with high rates of infection (at that time China, Iran, Italy, Japan, and South Korea) or risk factors for infection complications (including age or comorbid conditions) or the patient was a healthcare worker who could potentially expose others at risk comorbidities 101/235 (43.0%) (cases: 8/27 (29.6%), controls 93/208 (44.7%)) Demographics: age (< 18 years: 0.7%, 18‐64 years: 83.4%, > 65 years: 15.9%); gender: cases M/F%: 55.2/44.8; controls M/F%: 52.8/47.2; all M/F%: 53.0/47.0 Exposure history: recent travel (5.5%), 90.6% symptom‐based criteria for testing, no known exposure history based
Index tests	Fever
Target condition and reference standard(s)	TC: SARS‐CoV‐2 infection RS: Commercial RT‐PCR test ‐ ePLex SARS‐CoV‐2 test (nasopharyngeal swab)
Flow and timing	Probably no time interval between index test and RS, but 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?	Yes
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?	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?		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?	Yes
Could the patient flow have introduced bias?		Low risk