Pilarowski 2021.

Study characteristics
Patient Sampling	Single‐group study to estimate sensitivity and specificity: mainly asymptomatic suspected patients presenting at a walk‐up, free testing at a plaza located at an intersection of the Bay Area‐wide subway system (BART) and the San Francisco city bus/streetcar system (MUNI), Mission District, California Recruitment: not reported; appears to be all presenting for testing during study period Prospective or retrospective: prospective Sample size (cases): 878 (26)
Patient characteristics and setting	Setting: community screening/COVID‐19 test centre Location: walk‐up/free testing at a community plaza, San Francisco Country: USA Dates: September 2020 Symptoms and severity: mainly asymptomatic (84% reported no symptoms during the 14 days before testing) Demographics: 54% male; 77% 18‐50 years of age; 81% self‐identified as Latinx Exposure history: not reported
Index tests	Test name: BinaxNOW COVID‐19 Ag Card Manufacturer: Abbott Laboratories Antibody: N protein Ag target: not reported Test method: CGIA Samples used: AN (both nares) (Laboratory technician) Transport media: none required Sample storage: none reported Test operator: laboratory technician; on site Definition of test positivity: visual colour band; each assay was read by 2 independent observers, and a site supervisor served as a tiebreaker. Interpretation amended following first 217 samples because of high FP (9/207 PCR−ve); bands were subsequently scored as positive only if they extended across the full width of the strip, irrespective of the intensity of the band Blinding reported: yes; performed before PCR Timing of samples: mainly asymptomatic; timing not systematically reported for symptomatic group
Target condition and reference standard(s)	Reference standard: PCR (no further details, 2 prior studies cited for reference); in‐vitro culture Definition of non‐COVID cases: single negative PCR Genetic target(s): not reported Samples used: AN, paired Timing of reference standard: same as for index Blinded to index test: unclear Incorporated index test: no
Flow and timing	Time interval between index and reference tests: simultaneous, paired All participants received same reference standard: yes Missing data: unclear; 871/878 in the analysis Uninterpretable results: none reported Indeterminate results (index test): none reported Indeterminate results (reference standard): none reported Unit of analysis: participant
Comparative
Notes	Funding: "this study was supported by the University of California, San Francisco, the Chan Zuckerberg Biohub, the Chan Zuckerberg Initiative, the San Francisco Latino Task Force, the National Institute of Allergy and Infectious Diseases (grants T32 AI060530 to LR and F31AI150007 to SS), and a private donor." Publication status: published Source: Journal of Infectious Diseases Author COI: all authors reported no COI present
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 inclusions?	Yes
Could the selection of patients have introduced bias?		Low risk
Are there concerns that the included patients and setting do not match the review question?			Low concern
DOMAIN 2: Index Test (Evaluations of single test application)
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?	Yes
Could the conduct or interpretation of the index test have introduced bias?		Low risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
DOMAIN 2: Index Test (Evaluations of serial (repeat) testing)
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
Reference standard does not incorporate result of index test?	Yes
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?	Yes
Did all patients receive the same reference standard?	Yes
Were all patients included in the analysis?	No
Did all participants receive a reference standard?	Yes
Could the patient flow have introduced bias?		Low risk