Kruger 2020(c).

Study characteristics
Patient Sampling	Single group study to estimate sensitivity and specificity of three assays (each tested on a separate cohort of individuals, and extracted as three entries Kruger 2020(a), Kruger 2020(b), Kruger 2020(c). Participants at risk for SARS‐CoV‐2 infection based on exposure to a confirmed case, suggestive symptoms, or travel to a high risk area, presenting at one of three sites: (1) drive‐in testing station (n=1213) (2) a clinical ambulatory testing facility (n=1308) (3) secondary care facility (n=53) This entry (Kruger 2020(c)) relates to the 1263 participants tested with assay (c) from SD Biosensor; it is unclear whether some particpants may have receieved more than one assay *This study was also reported as three independent FIND evaluations; author contact advised including data from the Kruger et al pre‐print Recruitment: Not stated; recorded as consecutive, as per FIND evaluation protocol Prospective or retrospective: Prospective
Patient characteristics and setting	Setting: Mixed; (1), (2) Community (drive‐in or clinical ambulatory testing); (3) secondary care Location: Three sites: (1) Heidelberg, Germany; (2) Berlin, Germany and (3) Liverpool University Hospital Foundation Trust, Liverpool Country: (1), (2) Germany, (3) UK Dates: April 17th and August 25th, 2020; dates varied by assay and site Whole sample: Symptomatic on testing day (n=1901/2355, 80.7%) N with prior negative test result (n=236/1928, 12.2%) Mean age (SD) (n=2405: 40.4y (14.3)) Male (%) (n=1115/2361, 47.2%) Participants undergoing assay (b) (denominator back‐calculated from n and %) Symptomatic on testing day: 1054/1249, 84.4% N with prior negative test result: 125/1000, 12.5% Mean age (SD): 37.6 (12.7) Male (%): 49.8% Exposure history: Not stated
Index tests	Study reports data for three Ag assays, each tested on a separate cohort of individuals. See Kruger 2020(a) and Kruger 2020(b) for details of the other assays Test name:STANDARD Q COVID‐19 Ag Test Manufacturer: SD Biosensor, Inc. Gyeonggi‐do, Korea Antibody: Not stated Antigen target: Not stated Test method: CGIA Samples used: Drive‐in centre: NP or OP Other centres: combined NOP (OP conducted first) RT‐PCR swab obtained first, then same technique repeated for Ag test. Transport media: None; used manufacturer supplied buffer solution as per IFU Sample storage: Drive‐in centre and ambulatory testing: tested on site (presume short time frame) Secondary care: transported on ice to a category 3 facility for testing RT‐PCR swab obtained first, then same technique repeated for Ag test. Test operator: Drive‐in and ambulatory clinic: POC evaluation Secondary care: laboratory staff Definition of test positivity: Visual appearance were interpreted by two operators, each blinded to the result of the other. In case of discrepant results, both operators re‐read the result and agreed on a final result. Invalid results were repeated once using the remaining buffer according to the respective IFUs. Readouts were done within the recommended time for each Ag‐RDT (10 minutes for Bioeasy, 15 minutes for Coris and 15 to 30 minutes for SD Biosensor). Blinding reported: Yes; "Staff performing the Ag‐RDTs were blinded to results of RT‐PCR tests and vice versa" Timing of samples: Overall: mean 5 days pso (SD 9.6); this assay 3.7 days (SD 5.6)
Target condition and reference standard(s)	Reference standard: RT‐PCR; varied by site Drive‐in samples (Heidelberg): TibMolbiol (Berlin, Germany); the Allplex SARS‐CoV‐2 Assay from Seegene (Seoul, South Korea); or the Abbott (Illinois, US) RealTime 2019‐nCoV assay Ambulatory testing (Berlin): Roche Cobas SARS CoV‐2 assay (Pleasanton, CA United States) on the Cobas® 6800 or 8800 system; SARS CoV‐2 assay from TibMolbiol (Berlin, Germany) Secondary care (UK): Genesig® Real‐Time Coronavirus COVID‐19 PCR assay (Genesig, UK) Samples that showed a signal above the threshold in the relevant RT‐PCR target regions for each assay were considered to be positive Definition of non‐COVID cases: As per cases; single negative result Genetic target(s): Not stated Samples used: Paired swabs; as per index test (RT‐PCR swab obtained first,) Drive‐in centre: NP or OP Other centres: combined NOP (OP conducted first) Timing of reference standard: As per index test Blinded to index test: Yes; "Staff performing the Ag‐RDTs were blinded to results of RT‐PCR tests and vice versa" Incorporated index test: No
Flow and timing	Time interval between index and reference tests: Paired; simultaneous All patients received same reference standard: Yes (different assays) Missing data: 154 excluded following enrolment [116 2nd swab refused, 3 nose bleed after 1st swab, 3 insufficient time for both swabs, 31 other reasons, 1 no reason available] Uninterpretable results: 2 invalid (PCR negative); [B] 8 invalid (PCR negative); [C] 0 invalid reported PCR: 3 excluded as invalid (n=2) or not available (n=1) Indeterminate results (index test): None reported; Ease of use assessment reported: [A] a high number of test execution steps (including precision pipetting) … challenges when performing multiple tests at the same time possibly hindering the test’s wide‐spread use [B] challenges due to inconsistent test result interpretation (often only very faint lines visible) and deficiencies in both the test kit quality and design [C] no dissatisfactory scores identified Indeterminate results (reference standard): None reported Unit of analysis: Patients
Comparative
Notes	Study reports an ease of use assessment; for this assay: no dissatisfactory scores identified Funding: Study was supported by FIND, Heidelberg University Hospital and Charité – University Hospital internal funds. Pfizer funded the clinical team in Liverpool, UK. Publication status: Pre‐print Source: medRxiv Author COI: No COI statement reported; "external funders of the study had no role in study design, data collection, or data analysis"
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 exclusions?	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 (Antigen tests)
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 (Rapid molecular tests)
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?	Yes
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?	Yes
Did all participants receive a reference standard?	Yes
Were results presented per patient?	Yes
Could the patient flow have introduced bias?		Low risk