Hogan 2020.

Study characteristics
Patient Sampling	Single‐group design to estimate sensitivity and specificity ‐ samples from adult patients from 1 hospital and paediatric and adult samples from surrounding hospitals Recruitment: unclear; equal numbers of positive and negative RT‐PCR samples (suspect deliberate sampling by PCR result) Prospective or retrospective: not stated Number of samples (samples with confirmed SARS‐CoV‐2): 100 (50)
Patient characteristics and setting	Setting: hospital; not stated if inpatient or outpatient (samples selected from clinical virology laboratory) Location: Stanford Health Care (hospital), and surrounding hospitals (not named) Country: USA Dates: 7‐13 April 2020 Symptoms and severity: not stated Demographics: not stated Exposure history: not stated
Index tests	Test name: Accula SARS‐CoV‐2 POCT (no product code reported) Manufacturer: Mesa Biotech, Inc., San Diego, CA Antigen target: N gene Antibody: N/A Test method: rapid PCR Samples used: NP swabs in VTM (n = 37) or saline (n = 63, including 37 positive on RT‐PCR) Transport media: not stated; 10 μL of VTM or saline was transferred to 60 μL of SARS‐CoV‐2 buffer within a biosafety cabinet (not covered by manufacturer IFU) Sample storage: not stated; testing appears to have been conducted soon after sample collection Test operator: not stated; presume laboratory staff Definition of test positivity: as per manufacturer Blinding reported: not stated Timing of samples: not stated
Target condition and reference standard(s)	Reference standard: RT‐PCR; in‐house SHC assay (cites Hogan 2020 10.1016/j.jcv.2020.104383:104383) Definition of non‐COVID cases: single RT‐PCR negative Genetic target(s): E gene Samples used: NP swabs, same as for index test 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: not stated but implies that both tests undertaken in laboratory soon after sample collection All participants received same reference standard: yes Missing data: none reported Uninterpretable results: 3 invalid results were re‐tested; 1 positive and 2 negative Indeterminate results (index test): 1 known RT‐PCR‐positive sample that showed a faint positive test line was re‐tested and again showed the same faint test line (considered positive) Indeterminate results (reference standard): none reported Unit of analysis: refers to participants
Comparative
Notes	Funding: study authors report no specific funding Publication status: preprint Source: medRxiv Author COI: authors declare 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?	Unclear
Was a case‐control design avoided?	Unclear
Did the study avoid inappropriate exclusions?	Unclear
Did the study avoid inappropriate inclusions?	Unclear
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?			High
DOMAIN 2: Index Test (Antigen tests)
DOMAIN 2: Index Test (Rapid PCR 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?			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