Smithgall 2020 [A].

Study characteristics
Patient Sampling	Two‐group study to estimate sensitivity and specificity: ‐ patients undergoing routine clinical testing by RT‐PCR (n = 113) Recruitment: unclear; describes deliberate sampling of samples with high, medium and low Ct values on the reference standard RT‐PCR Prospective or retrospective: unclear; residual swabs used but testing undertaken within 48 h of sample collection Number of samples (samples with confirmed SARS‐CoV‐2): 113 (88)
Patient characteristics and setting	Setting: inpatient and ED (n from each not reported) Location: not stated; author institution is Columbia University Irving Medical Centre Country: USA Dates: 8‐13 April 2020 Symptoms and severity: not stated Demographics: 111 adult (range 23‐101 years; average 65 years for RT‐PCR‐positive and 43 years for RT‐PCR‐negative); 2 paediatric (age 1 day and 5 days) 61, 54% male Exposure history: not stated
Index tests	Test name: [A] ID NOW (see Smithgall 2020 [B] for details of comparator test) (product codes not reported) Manufacturer: [A] Abbott Antigen target: [A] RdRp gene Antibody: N/A Test method: [A] isothermal PCR Samples used: residual NP swabs (collection not described) Transport media: 3 mL VTM (M4RT VTM; ThermoFisher Scientific, Waltham, MA) or UTM (UTM; Becton Dickinson and Co., Franklin Lakes, NJ) Sample storage: stored at 4 °C; testing completed within 48 h of sample collection Test operator: not stated; presume laboratory staff Definition of test positivity: automated as per manufacturer Blinding reported: not stated Timing of samples: not stated; presume on admission or presentation at ED
Target condition and reference standard(s)	Reference standard: RT‐PCR with cobas SARS‐CoV‐2 assay on the 6800 platform (Roche Diagnostics, Indianapolis, IN); threshold not stated, all Ct values < 37 on both target genes Definition of non‐COVID cases: not stated; presume single RT‐PCR negative Genetic target(s): ORF1 a/b, E‐gene Samples used: as for index test Timing of reference standard: as for index test Blinded to index test: as for index test Incorporated index test: no
Flow and timing	Time interval between index and reference tests: simultaneous; same samples used All participants received same reference standard: yes Missing data: none reported Uninterpretable results: Indeterminate results (index test): Xpert: 1 sample was a presumptive positive based on detection of E‐gene target but not the N2 target Indeterminate results (reference standard): none reported Unit of analysis: participants
Comparative
Notes	Funding: none reported Publication status: published Source: Journal of Clinical Virology Author COI: study authors report no conflicts of interest present
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	No
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 (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?	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?			High
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