Perez‐Garcia 2020(a).

Study characteristics
Patient Sampling	Purpose: Study aimed to evaluate the diagnostic performance of a serologic rapid test in COVID‐19‐positive patients, COVID‐19‐negative patients with pneumonia, and pre‐pandemic patients. Three‐group study to estimate sensitivity and specificity for diagnosis of active disease and identification of previous disease. Design: [1] randomly selected group of pre‐pandemic patients who had a serum sample taken for other serologic studies (n = 100) [2] patients admitted to the Emergency department with suspicion of COVID‐19 and PCR‐positive for SARS‐CoV‐2 (n = 90) [3] patients admitted for at least 5 days with a clinical and radiological diagnosis of pneumonia of unknown aetiology, PCR‐negative for SARS‐CoV‐2 (n = 61) Recruitment: [1] a randomly selected group of 100 pre‐pandemic serologic samples [2] patients admitted to the Emergency department with suspicion of COVID‐19 and PCR‐positive for SARS‐CoV‐2 [3] patients admitted for at least 5 days with pneumonia of unknown aetiology and a clinical diagnosis of COVID‐19 with negative PCR for SARS‐CoV‐2 (included as Perez‐Garcia 2020(b) Prospective or retrospective: [1] and [2] Retrospective ("Since the present study is retrospective, informed consent was not required.") [3] Prospective ("Fresh serum samples from these 61 patients were studied." "They were prospectively studied after the validation of the serologic test.") Sample size: 251 (151) Further detail: Not stated
Patient characteristics and setting	Setting: [2] ED [14 (15.6 %) of them were discharged from ED, remaining 76 (84.4 %) patients were admitted to our hospital and 11 (14.5 %) required ICU admission] [3] inpatient Location: [2] and [3] Hospital Universitario Príncipe De Asturias, Madrid, Spain Country: [2] and [3] Spain Dates: [2] March 1 to April 6, 2020 [3] February 9 to April 2, 2020 Symptoms and severity: [2] Mild: 17/90 (18.9%) Non‐severe pneumonia: 47/90 (52.2%) Severe pneumonia: 20/90 (22.2%) Critical: 6/90 (6.7%) (3 ARDS and 3 with septic shock) [3] Mild: 0/61 (0.0%) Non‐severe pneumonia: 40/61 (65.6%) Severe pneumonia: 20/61 (32.8%) Critical (ARDS): 1/61 (1.6%) Demographics: [2] Age: median (IQR) 64 (55−79); 57.8% (52/90) male [3] Age: median (IQR) 67 (57‐73); 73.8% (45/61) male Exposure history: [2] and [3] Not stated Non‐Covid group 1: 1 Pre‐pandemic controls Source: patients who had a serum sample taken for other serologic studies, from September 1 to November 30, 2019 Characteristics: Age: median (IQR) 50 (33−65); 55% male
Index tests	Test name: AllTest COV‐19 IgG/IgM kit Manufacturer: AllTest Biotech, Hangzhou, China Antibody: IgG, IgM Antigen target: Unclear Evaluation setting: POC, performed in laboratory ("aliquots were previously obtained from samples sent to the laboratory to carry out other serologies") Test method: lateral flow immunoassay, LFA Timing of samples: [1] NA (pre‐pandemic) [2] median (IQR) days from symptom onset = 17 (9‐25) <= 7 days pso: 19/90 8‐14 days pso: 21/90 15‐21 days pso: 15/90 22‐28 days pso: 20/90 28 days pso: 15/90 [3] median (IQR) days from symptom onset = 17 (15‐20) <= 7 days pso: 0/61 8‐14 days pso: 15/61 15‐21 days pso: 31/61 22‐28 days pso: 14/61 28 days pso: 1/61 Samples used: Serum Test operator: Unclear Definition of test positivity: Visual Blinding reported: Unclear Threshold predefined:Yes, visual‐based.
Target condition and reference standard(s)	Reference standard: [2] and [3] RT‐PCR: VIASURE SARS‐CoV‐2 Real Time PCR Detection Kit (Certest Biotech, Zaragoza, Spain) and Allplex 2019‐nCoV assay (Seegene, Seoul, South Korea) [3] Clinical diagnosis of COVID‐19 with negative PCR for SARS‐CoV‐2. Criteria for diagnosis not stated Samples used: [2] and [3] Unclear ‐ "clinical samples" Timing of reference standard: [2] and [3] Unclear Blinded to index test: [2] and [3] Yes, prior to index test Incorporated index test: [2] and [3] No Definition of non‐COVID cases: [1] Pre‐pandemic = not tested Samples used: [1] pre‐pandemic Timing of reference standard: [1] Pre‐pandemic samples Blinded to index test: Yes, prior to index test Incorporated index test: No
Flow and timing	Time interval between index and reference tests: Not stated All patients received same reference standard: No Missing data: Not stated Uninterpretable results: Not stated Indeterminate results: Not stated Unit of analysis: Patients
Comparative
Notes	Funding: This research received no specific grant from any funding agency in the public, commercial, or not‐for‐profit sectors. Publication status: Published paper Source: Journal of Clinical Virology Author COI: The authors declared that they had no conflicts of interest.
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?	Unclear
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?	Unclear
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?	Yes
Did all participants receive a reference standard?	No
Were results presented per patient?	Yes
Could the patient flow have introduced bias?		High risk