Conklin 2020 [A].

Study characteristics
Patient Sampling	Purpose: Diagnosis of current acute‐phase infection and current convalescent‐phase infection Design: Multi‐group study to estimate sensitivity and specificity [1] Confirmed COVID patients, convalescent (n = 40) [2] Confirmed COVID samples, longitudinal testing (47 patients with 272 samples) [3] Pre‐pandemic non‐COVID challenge samples (60 patients) Recruitment: [1] Not stated [2] Not stated [3] These samples came from a study of patients presenting to the Johns Hopkins Hospital Emergency Department with symptoms of an acute respiratory tract infection between January 2016 and June of 2019 as part of the Johns Hopkins Center for Influenza Research and Surveillance study. Prospective or retrospective: [1] Unclear [2] Unclear [3] Retrospective Sample size: 372 (312) Further detail: [1] RT‐PCR positive for SARS‐CoV‐2 and asymptomatic for at least 28 days. Human immunodeficiency virus (HIV) and hepatitis C virus (HCV) negative [2] Hospitalised SARS‐CoV‐2 RT‐PCR‐confirmed patients [3] Patients presenting to the Johns Hopkins Hospital Emergency Department with symptoms of an acute respiratory tract infection between January 2016 and June of 2019. Samples that were known to represent infections with other respiratory viruses (rhinoviruses A, B, and C and/or coronavirus 229E, HKU1, and NL63 OC43)
Patient characteristics and setting	Setting: [1] Convalescent plasma donors (community?) [2] Hospital inpatients Location: [1] and [2] Not stated (Johns Hopkins University School of Medicine, Baltimore?) Samples evaluated were from the Baltimore‐Washington region of the United States. Country: [1] and [2] Maryland, USA Dates: [1] and [2] Not stated Symptoms and severity: [1] Convalescent, asymptomatic since at least 28 days [2] Fever 34 (72%) Cough 29 (62%) Difficulty breathing 24 (51%) Muscle/body pain 14 (30%) Chills 9 (19%) Weakness/fatigue 7 (15%) Sore throat 6 (13%) Other 31 (66%) Demographics: [1] Not stated [2] Age: Median 62 (IQR 44‐80) years 29 (62%) male Black/African American 23 (49%) White/Caucasian 17 (36%) Hispanic/Latino 4 (9%) Asian 2 (4%) Other 1 (2%) Exposure history: [1] and [2] Not stated Non‐Covid group 1: [3] Pre‐pandemic challenge Source: Johns Hopkins Hospital Emergency Department between January 2016 and June of 2019 Characteristics: Samples that were known to represent infections with other respiratory viruses (rhinoviruses A, B, and C and/or coronavirus 229E, HKU1, and NL63 OC43). Non‐Covid group 2: NA
Index tests	Test name: [A] AllTest [B] AYTU [C] Clarity [D] RightSign [E] Covisure [F] DNA Link [G] Nirmidas [H] Ready Result [I] EDI IgM ELISA [J] SafeCare [K] Sensing Self [L] Smart Screen [M] TBG SARS‐CoV‐2 IgG/IgM [N] Wondfo SARS‐CoV‐2 Ab [O] Zeus SARS‐CoV‐2 IgM/IgG [P] Euroimmun Anti‐SARS‐CoV‐2 IgG ELISA Manufacturer: [A] Hangzhou AllTest Biotech Co., Ltd. [B] AYTU Biosciences [C] Alfa Scientific Designs Inc. [D] Hangzhou Biotest Biotech Co., Ltd. [E] W.H.P.M., Inc. [F] Not stated [G] Nirmidas Biotech, Inc., and Lows Health [H] Hangzhou Biotest Biotech Co., Ltd. [I] Epitope Diagnostics, San Diego, CA [J] Safecare Biotech (Hangszhou) Co., Ltd. [K] Sensing Self, PTE. Ltd. [L] Intelligent Endoscopy [M] TBG Biotechnology Corp. [N] Wondfo Biotechnology [O] Zeus Scientific, Inc. [P] Euroimmun, Mountain Lakes, NJ Antibody: [A] IgM, IgG [B] IgM, IgG [C] IgM, IgG [D] IgM, IgG [E] IgM, IgG [F] IgM, IgG [G] IgM, IgG [H] IgM, IgG [I] IgM [J] IgM, IgG [K] IgM, IgG [L] IgM, IgG [M] IgM, IgG [N] IgM/IgG combined [O] IgM, IgG [P] IgG Antigen target: [A] N, S [B] N, S [C] N, S [D] RBD [E] Not stated [F] Not stated [G] S [H] N, S [I] Not stated [J] Not stated [K] N, S [L] Not stated [M] Not stated [N] Not stated [O] N, S [P] Not stated Evaluation setting: All POC tests apart from [I] and [P] Lab‐based Test method: [A] Lateral flow tests apart from [I] and [P] ELISAs Timing of samples: [1] 45 days (standard deviation [SD], +/‐7.5 days (at least 28 days asymptomatic). Figure 2a says "> 26 days" [2] Median 6 (IQR 4‐8) post‐symptom onset; Data Set S1 reported range from ‐2 to 36 days pso. Samples used: [1] and [2] Plasma [3] Serum Test operator: Not stated Definition of test positivity: [A]‐[O] All LFAs were performed according to the manufacturers’ protocols. Any detectable band (IgM and/or IgG) was considered a positive result. All LFAs, except Wondfo, had separate bands for IgM and IgG detection. Results were considered invalid when the control band was not visible. [P] and [Q] per the manufacturers’ protocols Blinding reported: Not stated Threshold predefined: Yes, visual‐based or as per manufacturer's protocols [I] and [P]
Target condition and reference standard(s)	Reference standard: [1] and [2] SARS‐CoV‐2 RT‐PCR, threshold not stated Samples used: [1] and [2] Not stated Timing of reference standard: [1] and [2] Not stated Blinded to index test: [1] and [2] yes, prior Incorporated index test: [1] and [2] no Definition of non‐COVID cases: [3] Pre‐pandemic Samples used: [3] Pre‐pandemic Timing of reference standard: [3] Pre‐pandemic Blinded to index test: [3] yes, prior Incorporated index test: [3] no
Flow and timing	Time interval between index and reference tests: Not stated All patients received same reference standard: No Missing data: yes (see Figure 2a, test [E] Covisure 3 invalid results, test [H] Premier Biotech 2 invalid results, test [F] DNA Link 1 no data; test [M] TBG 1 no data) Uninterpretable results: yes (3 invalid results for test [E], 2 invalid results for test [H], Figure 2a) Indeterminate results: Not stated Unit of analysis: [1] and [2] Patients [3] Samples
Comparative
Notes	Funding: The study was supported by the Division of Intramural Research, National Institute of Allergy and Infectious Diseases (NIAID), National Institutes of Health (NIH). Research reported in this publication was supported by the following research awards: from the NIAID, UM1‐AI068613, R01AI120938, and R01AI128779; from the National Institute of Biomedical Imaging and Bioengineering, U54EB007958; from the National Heart, Lung, and Blood Institute of the National Institutes of Health, 1K23HL151826‐01. The work described here was supported in part by NIAID contract HHSN272201400007C awarded to the Johns Hopkins Center for Influenza Research and Surveillance (JHCEIRS). Publication status: Published paper Source: Journal of Clinical Microbiology Author COI: E.M.B. is a member of the United States Food and Drug Administration (FDA) Blood Products Advisory Committee. Any views or opinions that are expressed in this article are ours, based on our own scientific expertise and professional judgment; they do not necessarily represent the views of either the Blood Products Advisory Committee or the formal position of FDA and also do not bind or otherwise obligate or commit either Advisory Committee or the Agency to the views expressed.
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?	Yes
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?		Low 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?	No
Did all participants receive a reference standard?	Yes
Were results presented per patient?	No
Could the patient flow have introduced bias?		High risk