Peto 2021(c) [A ‐ Lab tested].

Study characteristics
Patient Sampling	Set of studies conducted by PHE and University of Oxford. This extraction relates to a single‐group study estimating sensitivity alone: individuals presenting at 1 of 14 regional drive‐through COVID‐19 NHS Test and Trace centres as part of the FALCON C‐19 (Facilitating Accelerated Clinical validation Of Novel diagnostics for COVID‐19, 20/WA/0169, IRAS 284229) phase 3b study; those with a positive PCR result were asked to return for a re‐test within 5 days of the original test result. From the originally published report (November 2020) it appears that only participants with samples that were positive on PCR at the second sampling were included. (1) One set of samples were tested on site by HCWs using assay [A] only: n = 267; included as Peto 2021(c) [A ‐ HCW tested] (2) Second set of samples were tested in the laboratory by laboratory scientists using four different assays [A] to [D]: n = 212; included as Peto 2021(c) [A ‐ Lab tested], Peto 2021(c) [B ‐ Lab tested], Peto 2021(c) [C ‐ Lab tested], Peto 2021(c) [D ‐ Lab tested] See other PHE extractions for other sub‐studies of Innova assay Recruitment: not stated; presume consecutive Prospective or retrospective: prospective Number of samples (cases): 479 (479)
Patient characteristics and setting	Setting: NHS drive through Test and Trace centres; conducted within the FALCON‐C19 study Location: 14 regional centres Country: UK Dates: 17 Sept to 23 Oct 2020 Symptoms and severity: only described for 421 included participants combined: 381 (90%) symptomatic; 138 (36%) headache, 134 (35%) cough, 82 (22%) sore throat, 80 (21%) fever, 260 (68%) 'other' not specified symptoms, 59 with no data. 40 (10%) reported asymptomatic Demographics: median age 33 (91 with no data); 168/337 male, 50% (84 with no data recorded) Exposure history: not stated
Index tests	Comparative study of 4 Ag tests (no product codes reported); Peto 2021(c) [A ‐ HCW tested] and Peto 2021(c) [A ‐ Lab tested] data relate to test [A], see additional entries for tests [B] to [D] Test name: [A] Innova SARS‐CoV‐2 Antigen Rapid Qualitative Test [B] Panbio COVID‐19 Ag Rapid Test Device [C] Coronavirus Ag Rapid Test Cassette [D] Anhui Deepblue Medical Technology COVID‐19 Manufacturer: [A] Innova Medical Group [B] Abbott [C] Zhejiang Orient Gene Biotech [D] Deepblue Antibody: not stated Ag target: not stated Test method: not stated Samples used: combined AN and OP swabs (1 stored as a dry swab and 1 swab placed in VTM; swabs were self‐collected Transport media: dry swab Sample storage: (1) immediate on‐site testing by HCW (2) transport to PHE; tested within 24 h of collection Test operator: (1) Immediate testing by HCW (assay [A]) (2) laboratory scientist tested at PHE (assay [A] to [D]) Definition of test positivity: visual line; as per manufacturer IFU An invalid kit result, or a kit failure was recorded when an operator did not see a control line on the device within a defined time period Blinding reported: yes for on‐site HCW testing; lab scientists reported as unaware of clinical information from the study participants Timing of samples: not stated
Target condition and reference standard(s)	Reference standard: PCR; Roche Cobas 6800 or 8800 system using their proprietary SARS‐CoV‐2 assay Viral load conversion to RNA copies/mL was performed using the Qnostics SARS‐CoV‐2 Analytical Q Panel 01 (Qnostics, Glasgow, UK); the resulting equation for converting Ct values into viral loads for the Cobas assay, included an adjustment for the dilution, was log10(VL) = 14.17‐0.3316*avct Definition of non‐COVID cases: N/A; cases‐only study Genetic target(s): ORF‐1 and E‐gene Samples used: AN + OP Timing of reference standard: as for index test Blinded to index test: not stated Incorporated index test: no
Flow and timing	Time interval between index and reference tests: paired All participants received same reference standard: yes Missing data: yes; appears that only those who remained PCR+ on return for Ag testing were included (the original report (November 2020) documented 16 HCW‐tested samples that were either PCR−ve (n = 15) or void (n = 1) presumably at the time of the second sampling (partially explains discrepancy in numbers) Uninterpretable results: failure rates reported for assay [A] only as: HCW tested 27/267 10.1%; lab scientist tested 9/212 4.2%. NB preliminary report reported these as 28/296 and 9/221 respectively Indeterminate results (index test): unclear; Indeterminate results (reference standard): unclear Unit of analysis: participant
Comparative
Notes	Funding: PHE evaluation Publication status: published Source: online PHE report; published paper Author COI: none reported
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?	No
Did the study avoid inappropriate inclusions?	Yes
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 (Evaluations of single test application)
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 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?			High
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	No
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?		High risk