Cradic 2020(b).

Study characteristics
Patient Sampling	Single group study to estimate sensitivity and specificity: paired samples from patients presenting to ED with signs/symptoms of COVID‐19 submitted for routine laboratory testing (n=182) Recruitment: Not stated Prospective or retrospective: Prospective [Second cohort of symptomatic patients suspected of COVID‐19 that met criteria for testing, either presenting to ED or as inpatients at single hospital (n=184), extracted as Cradic 2020(a)]
Patient characteristics and setting	Setting: Emergency department Location: OhioHealth Laboratory Services, Columbus (presume ED at OhioHealth Riverside Methodist Hospital) Country: USA Dates: Not stated Symptoms and severity: All symptomatic, no further details. Demographics: Not stated Exposure history: Not stated
Index tests	Test name: [A] ID NOW COVID‐19 EUA [Study also evaluates [B] Diasorin Simplexa and [C] Roche cobas 6800 SARS‐CoV‐2; not eligible for this review] Manufacturer: Abbott Laboratories Target gene(s): RdRp Antigen target: n/a Test method: Isothermal PCR Samples used: NP swabs in UTM (collected as part of standard of care), plus direct testing of OP swabs and of nasal swabs (collected according to CDC instructions) Transport media: presume as above for NP in UTM Sample storage: not stated Test operator: Not stated; infer laboratory staff. Definition of test positivity: as per manufacturer Blinding reported: Not stated Timing of samples: Unclear, infer upon presentation
Target condition and reference standard(s)	Reference standard: RT‐PCR; Diasorin Simplexa Definition of non‐COVID cases: Same as index test; single negative for absence disease Genetic target(s): S or ORF1ab gene (either present) Samples used: NP swab in UTM Timing of reference standard: Not stated Blinded to index test: Not stated Incorporated index test: No
Flow and timing	Time interval between index and reference tests: Simultaneous; paired swabs All patients received same reference standard: Yes Missing data: None reported, no participant flow diagram reported Uninterpretable results: None reported Indeterminate results (index test): None reported Indeterminate results (reference standard): None reported Unit of analysis: Patients
Comparative
Notes	Funding: No funding statement reported Publication status: published Source: American Journal of Clinical Pathology Author COI: No COI statement reported
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 (Antigen tests)
DOMAIN 2: Index Test (Rapid molecular 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?			Unclear
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
Reference standard does not incorporate result of index test?	Yes
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?	Yes
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