Candel 2020.

Study characteristics
Patient Sampling	Purpose: To analyse the accuracy of a point‐of‐care SARS‐CoV‐2 IgM and/or IgG rapid test for the diagnosis of COVID‐19, and to correlate this pattern of immune response with the severity of disease. 2‐group study to estimate sensitivity and specificity for diagnosis of active disease and identification of previous disease. Only 1 group (sensitivity only) included in our review Design: Two‐group study: [1] randomly selected SARS‐CoV‐2 RT‐PCR confirmed patients (n = 35) [2] healthy volunteers with no history of COVID‐19 symptoms and negative SARS‐CoV‐2 RT‐PCR (n = 5) Group [2] excluded from review as <25 controls. Recruitment: [1] randomly selected SARS‐CoV‐2 RT‐PCR confirmed patients, admitted to IFEMA Field Hospital between April 27th and April 29th, 2020 [2] source of recruitment unclear Prospective or retrospective: Prospective Sample size: 40 (35) of which 35 (35) were eligible for our review Further detail: [1] positive RT‐PCR for pharyngeal swabs [2] healthy, nonsymptomatic, negative RT‐PCR
Patient characteristics and setting	Setting: Hospital inpatient Location: 1400‐bed field hospital set up at IFEMA (Institución Ferial de Madrid/Ferial Institution of Madrid) Country: Spain Dates: Recruitment April 27th to April 29th, 2020 Symptoms and severity: Mild = 3; Moderate = 9; Severe = 21; Critical = 2 12 (34.3%) mild‐moderate 23 (65.7%) severe‐critical 31/35 (88.6%) bilateral pneumonia Demographics: Female 21/35; mean age 58.2 years (COVID‐19 positive patients only) Exposure history: Not stated Non‐Covid group 1: NA
Index tests	Test name: Autobio rapid lateral‐flow point‐of‐care antibody test Anti‐SARS‐CoV‐2 Rapid Test Manufacturer: Autobio Diagnostics Co. Zhengzhou, China Antibody: IgM, IgG Antigen target: SARS‐CoV‐2 recombinant spike‐protein antigen Evaluation setting: POC, used as POC Test method: Lateral flow immunoassay (colloidal gold) (CGIA) Timing of samples: The average time from the first day of reported symptoms to the lateral flow test was 28 days (SD: 8.7). The ranges were similar between the mild‐moderate cases (minimum: 17 days; maximum: 45 days) and the severe‐critical (minimum: 16 days; maximum: 48 days). Samples used: Whole blood Test operator: Not stated Definition of test positivity: According to the manufacturer instructions, IgG band reading rendered either negative or positive results. On the other hand, IgM band was classified as either negative, positive or weak positive depending on the intensity of the band staining. IgM‐positive, IgG‐positive and either IgM or IgG‐positive band staining were counted as positive results for the rapid test. A picture of every rapid test was taken at the manufacturer’s established time of reading. Test results were evaluated by two operators. In case of disagreement, a third operator was requested. Blinding reported: Not stated, but unlikely ‐ controls were healthy volunteers whereas cases were inpatients Threshold predefined: Visual, interpreted as per manufacturer's instructions
Target condition and reference standard(s)	Reference standard: SARS‐CoV‐2 positive RT‐PCR for pharyngeal swabs; threshold not stated Samples used: pharyngeal swabs Timing of reference standard: Not stated Blinded to index test: Yes ‐ index test was done 16‐48 days after symptom onset Incorporated index test: No ‐ index test was done 16‐48 days after symptom onset Definition of non‐COVID cases: NA
Flow and timing	Time interval between index and reference tests: Not stated [2] Not stated All patients received same reference standard: Yes ‐ RT‐PCR Missing data: None Uninterpretable results: Not reported Indeterminate results: Not reported Unit of analysis: Patients
Comparative
Notes	Funding: None to declare Publication status: Published Source: Journal: Revista Española de Quimioterapia (Official Journal of the Spanish Society of Chemotherapy) 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?	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?	No
If a threshold was used, was it pre‐specified?	Yes
Could the conduct or interpretation of the index test have introduced bias?		High risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
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?	Yes
Were all patients included in the analysis?	Yes
Did all participants receive a reference standard?	Unclear
Were results presented per patient?	Yes
Could the patient flow have introduced bias?		Unclear risk