McAulay 2020 [A].

Study characteristics
Patient Sampling	Purpose: Two‐group study to estimate sensitivity and specificity for diagnosis of active disease and identification of previous disease. Design: [1] RT‐PCR‐positive COVID‐19 patients (predominantly hospitalised (n = 62 patients, 352 samples, Seattle cohort) [2] Specificity group: 74 pre‐pandemic clinical serum specimens and 31 “cross‐reactivity challenge” specimens (27 from individuals with a history of seasonal coronavirus infection within 3 years prior to collection and 4 specimens reactive for rheumatoid factor, HIV‐1 antibody, HAV total antibody, HBV core total antibody and surface antibody, HCV antibody and/or HSV2 antibody) (n = 105 people) Recruitment: [1] Samples were kindly shared by the Department of Laboratory Medicine at the University of Washington School of Medicine (Seattle, WA) [2] Unclear Prospective or retrospective: Retrospective Sample size: Samples: 457 (352). People: 167 (62) Further detail: [1] reverse‐transcription polymerase chain reaction (RT‐PCR)–confirmed COVID‐19 [2] Not stated
Patient characteristics and setting	Setting: "primarily hospitalised individuals with COVID‐19" (Supplementary Table S1) Location: Samples from Department of Laboratory Medicine at the University of Washington School of Medicine (Seattle, WA) Country: USA Dates: Not stated Symptoms and severity: Not stated Demographics: Not stated Exposure history: Not stated Non‐Covid group 1: [2] Specificity cohort (pre‐pandemic other disease or concurrent cross‐reactivity) Source: [2] 2 sources: 74 excess clinical serum specimens collected and stored in 2018, and 31 “cross‐reactivity challenge” specimens collected between March and April 2020 Characteristics: [2] 74 pre‐pandemic clinical samples: not stated; 31 "cross‐reactivity challenge" specimens: 27 from individuals with a history of seasonal coronavirus infection (as determined by a syndromic respiratory PCR test) within 3 years prior to collection (HKU1, n = 13; NL63, n = 6; OC43, n = 6; 229E, n = 2); 2 specimens reactive for rheumatoid factor; 1 reactive for HIV‐1 antibody, HAV total antibody, HBV core total antibody and surface antibody, and RPR; and 1 reactive for HCV antibody and HSV2 antibody
Index tests	Test name: [A] Rapid ResponseTM COVID‐19 Test Cassette (BTNX Inc.) Kit1 [B] SARS‐COV‐2 IgG/IgM Rapid Test (ACON Laboratories) [C]] Standard Q COVID‐19 IgM/IgG Duo (SD BIOSENSOR) [D] SARS‐CoV‐2 IgG immunoassay Manufacturer: [A] BTNX Inc. [B] ACON Laboratories [C] SD BIOSENSOR [D] Abbott Antibody: [A] IgM/IgG [B] IIgM/IgG [C] IgG (This kit was supplied as individual IgM and IgG cartridges; only the IgG cartridges were evaluated in this study) [D] IgG Antigen target: [A] Not stated [B] Not stated [C] N [D] N Evaluation setting: [A] POC, used in laboratory (Clinical Laboratory Improvement Amendments laboratory setting) [B] POC, used in laboratory (Clinical Laboratory Improvement Amendments laboratory setting) [C] POC, used in laboratory (Clinical Laboratory Improvement Amendments laboratory setting) [D] Lab test used in lab [Department of Laboratory Medicine at the University of Washington School of Medicine (Seattle, WA)] Test method: [A] Lateral Flow Immunoassay (LFIA) [B] Lateral Flow Immunoassay (LFIA) [C] Lateral Flow Immunoassay (LFIA) [D] CLIA Timing of samples: 1 to 31 days post‐symptom onset (Supplementary Table S1) < 7 days pso: 154/352 7‐13 days pso: 103/352 14‐31 days pso: 95/352 Samples used: [1] Mixed: 250 plasma, 77 serum, and 21 whole blood specimens (a further four unknown specimens were assumed to be either serum or plasma) received frozen; and underwent either 1 or 2 freeze–thaw cycles prior to testing. [2] Pre‐pandemic samples: 74 serum; Cross‐reactivity samples: not stated Test operator: [A]‐[D] Laboratory personnel Definition of test positivity: [A]‐[D] Visible lines Blinding reported: [A]‐[D] Yes Threshold predefined: As per manufacturer
Target condition and reference standard(s)	Reference standard: RT‐PCR ("RT‐PCR‐confirmed COVID‐19") Samples used: Not stated Timing of reference standard: Not stated Blinded to index test: Yes, prior Incorporated index test: No Definition of non‐COVID cases: Pre‐pandemic and “cross‐reactivity challenge” specimens determined by a syndromic respiratory PCR test Samples used: Pre‐pandemic and not stated Timing of reference standard: Pre‐pandemic and not stated Blinded to index test: Yes, prior Incorporated index test: No
Flow and timing	Time interval between index and reference tests: Not stated for [1] and pre‐pandemic samples from [2] [2] Cross‐reactivity samples: 4 samples on the same day 27 samples: 1‐1159 days (within 3 years) All patients received same reference standard: No ‐ some pre‐pandemic Missing data: Yes (not all samples tested with tests [C], [D] and [E]: [C] only included 95 samples 14+ days pso; [D] only included 50 samples 14+ days pso; [E] 268/352 samples included in analyses) Uninterpretable results: 1 invalid result in specificity group excluded Indeterminate results: Not stated Unit of analysis: [1] Samples (Some patients had even several samples taken at the same day) [2] Patients
Comparative
Notes	Funding: This research did not receive any specific grant from funding agencies in the public, commercial, or not‐for‐profit sectors. We would also like to thank the manufacturers for supplying some of the kits (ACON and BTNX kit 1). We also thank Safe Health Systems who supplied some kits (SD and BTNX kit 2) as part of a joint partnership with Mayo Clinic. Publication status: Pre‐print (not peer reviewed); now published Source: medRxiv preprint Journal (Diagnostic Microbiology and Infectious Disease) Author COI: TEG represents Mayo Clinic in a joint venture with Safe Health Systems and has shared intellectual property that may result in royalty sharing.
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?	No
Did the study avoid inappropriate exclusions?	Unclear
Did the study avoid inappropriate inclusions?	No
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 (All tests)
DOMAIN 2: Index Test (Antibody 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?			Unclear
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Unclear
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
The reference standard does not incorporate the 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?	Unclear
Did all patients receive the same reference standard?	No
Were all patients included in the analysis?	Unclear
Did all participants receive a reference standard?	No
Were results presented per patient?	No
Could the patient flow have introduced bias?		High risk