Dortet 2020.

Study characteristics
Patient Sampling	Purpose: to assess the rapid test's diagnostic accuracy and clinical utility for patient management 2‐group study to estimate sensitivity and specificity for diagnosis of active disease/identification of previous disease Design: [1] RT‐PCR‐confirmed COVID‐19 patients (n = 101, 256 sera samples) [2] Non‐COVID‐19 controls (n = 50: 22 healthy volunteers, 24 pre‐pandemic; 4 RT‐PCR‐negative with common coronaviruses) Recruitment: Unclear Prospective or retrospective: [1] Prospective at time of COVID‐specific consultation or ER attendance. RT‐PCR samples taken at same attendance as serum [2] Retrospective in 24 pre‐pandemic samples, prospective in 22 healthy volunteers, and unclear for 4 PCR‐negative samples Sample size: 151 (101) patients with 306 (256) samples Further detail: Not stated
Patient characteristics and setting	Setting: Inpatients and ER consultations Location: Hôpital Bicêtre, AP‐HP; Le Kremlin‐Bicêtre, France; Hôpital Paul‐Brousse, AP‐HP; Villejuif, France Country: France Dates: March 11–23 2020 Symptoms and severity: 17.8% (18/101) were discharged 72.3% (72/101) were hospitalised in a dedicated COVID ward 10.9% (11/101) were critically ill and required immediate hospitalisation in the ICU Demographics: male/female ratio was 1.46; median age was 58 years (IQR, 35‐61) Exposure history: Not stated Non‐Covid group 1: Non‐COVID‐19 controls Source: 22 healthy volunteers and 4 RT‐PCR‐negative with common coronaviruses = contemporaneous; 24 pre‐pandemic = September‐October 2017 Characteristics: Not stated for 24 pre‐pandemic samples 4 from patients with respiratory symptoms that were RT–PCR‐negative for SARS‐CoV‐2 but positive for common coronaviruses (Coronavirus HKU1 (n = 2), NL63 (n = 1), 229E (n = 1)), recent common coronavirus infections in the past 3‐months; 22 healthy volunteers without any respiratory symptoms
Index tests	Test name: NG‐Test IgM‐IgG COVID All‐in‐one Manufacturer: NG Biotech, Guipry, France Antibody: IgM, IgG Antigen target: Nucleocapsid protein Evaluation setting: POC, applied POC for healthy volunteers but unclear for the other participants (retrospective analysis from stored sera) Test method: lateral flow immunoassay Timing of samples: For 97 patients, days 1‐11 after hospitalisation Most sera were sampled between day 0–15 after the onset of symptoms (85.5%, 219/256) Samples used: Serum for [1] and [2], pre‐pandemic and PCR‐negative samples or a drop of blood (after finger puncture) for [2, healthy volunteers] Test operator: Unclear Definition of test positivity: Results were read after 15 minutes according to the manufacturer’s recommendations, visual‐based Blinding reported: Not stated Threshold predefined: Yes
Target condition and reference standard(s)	Reference standard: Real‐time RT‐PCR targeting RNA‐dependent RNA polymerase and E genes Samples used: Nasopharyngeal samples Timing of reference standard: The average time between the onset of symptoms and receiving an RT‐PCR result was 5.4 (± 0.4) days Blinded to index test: Yes, done prior index test Incorporated index test: No Definition of non‐COVID cases: Mixed Pre‐pandemic (September/October 2017) (n = 24) RT‐PCR‐negative for SARS‐COV‐2 (n = 4) No respiratory symptoms for healthy volunteers (n = 22) Samples used: None Timing of reference standard: NA for pre‐pandemic samples and healthy volunteers Blinded to index test: Unclear for healthy volunteers (tested directly using a drop of whole blood) Incorporated index test: No
Flow and timing	Time interval between index and reference tests: done during same consultation for 97 COVID‐19 samples, unclear for the remaining samples All patients received same reference standard: No Missing data: Not stated Uninterpretable results: Not stated Indeterminate results: Not stated Unit of analysis: Samples
Comparative
Notes	Funding: This research was supported by Assistance Publique–Hôpitaux de Paris (APHP), Médecins Sans Frontières (MSF), and by a Grant from the French Defence Innovation Agency (AID). We acknowledge NG Biotech for providing free testing devices. Publication status: Submitted to Lancet Infectious Diseases; now published article Source: Editorial Manager® and ProduXion Manager® from Aries Systems Corporation Journal: Emerging Microbes and Infections Author COI: The authors declared no conflict 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?			Unclear
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?	Unclear
The reference standard does not incorporate the 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?	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