Zhang 2020a [A].

Study characteristics
Patient Sampling	Purpose: Diagnosis of current acute and convalescent‐phase infection Design: Multi‐group study to assess sensitivity and specificity [1] Covid cases (572 samples) [1a] confirmed hospitalised cases (338 samples from 164 patients) [1b] Follow‐up cases (234 samples from 234 patients) [2] Non‐Covid cases (n = 996) [2a] Healthy controls (n = 600) [2b] With other diseases (n = 396) [3] Suspected COVID patients (162 samples from 154 patients) Recruitment: Samples obtained between December 2019 and March 2020 from Wuhan Recruitment method not stated. Prospective or retrospective: Retrospective Sample size: 1730 (574) samples Further detail: [1] Inclusion: Hospitalised clinically confirmed Covid patients. Exclusion: Not stated [2a] Inclusion: Healthy. Exclusion: Not stated [2b] Inclusion: Other diseases, respiratory disease (n = 57), orthopaedic disease (n = 8), hepatobiliary disease (n = 48), gynaecological disease (n = 50), auto‐immune disease (n = 10), endocrine disease (n = 41), dermal disease (n = 18), nervous system disease (n = 13), kidney disease (n = 32), digestive disease (n = 64), cardiovascular disease (n = 24), blood disease (n = 21), other disease (n = 10). Exclusion: Not stated. [3] Suspected COVID cases, close contact with COVID patients
Patient characteristics and setting	Setting: [1a] Hospitalised [1b] Outpatients/community (follow‐up patients) [3] close contacts with COVID patients (screening) Location: Wuhan Huoshenshan Hospital, Wuhan, First Hospital of Changsha, Changsha, and Chinese PLA General Hospital, Beijing Country: China Dates: December 2019 to March 2020 Symptoms and severity: [1a] Ordinary cases (n = 141), severe cases (n = 23) based on the diagnosis and treatment of novel coronavirus pneumonia (trial version 6) [1b] Not stated [3] 153/154 asymptomatic (no fever, no abnormalities in CT image) 1/154 first asymptomatic; later developed fever Demographics: [1a] Male (n = 92), female (n = 72), age range 25‐91 years, median age 62 years [1b] male (n = 115), female (n = 119), age range 1‐84 years, median age 49 years [3] Not stated Exposure history: [1] Not stated [3] Close contacts of confirmed COVID patients. Non‐Covid group 1: [2a] Healthy controls Source: [2a] December 2019 to March 2020, Wuhan Huoshenshan Hospital, First Hospital of Changsha and Chinese PLA General Hospital? Characteristics: Healthy, male, n = 313, female, n = 287; age range: 9–74, median age: 45 years Non‐Covid group 2: [2b] With other diseases Source: December 2019 to March 2020, Wuhan Huoshenshan Hospital, First Hospital of Changsha and Chinese PLA General Hospital? Characteristics: male, n = 185, female, n = 211; age range: 1–94, median age: 50 years, respiratory disease (n = 57), orthopaedic disease (n = 8), hepatobiliary disease (n = 48), gynaecological disease (n = 50), auto‐immune disease (n = 10), endocrine diseases (n = 41), dermal disease (n = 18), nervous system diseases (n = 13), kidney disease (n = 32), digestive disease (n = 64), cardiovascular disease (n = 24), blood diseases (n = 21), other diseases (neonatal diseases, oral diseases) (n = 10)
Index tests	Test name: [A] 2019‐nCoV IgM Antibody Determination Kit [B] 2019‐nCoV IgG Antibody Determination Kit Manufacturer: [A] [B] Beijing Diagreat Biotechnology Co., Ltd., Beijing, People’s Republic of China Antibody: [A] IgM [B] IgG Antigen target: [A] [B] S1 and N‐protein Evaluation setting: POCT, unclear setting Test method: [A] [B] Fluorescence‐based lateral flow assay Timing of samples: [1] 0‐70 days of onset of fever [1a] < 15 days pso: n = 9 15‐21 days pso (n = 38) > 21 days pso (n = 291) [1b] > 21 days pso: n = 234 [3] Asymptomatic Samples used: whole blood Test operator: Lab staff Definition of test positivity: The 95% percentile of the T/C ratio (the ratio between the fluorescence intensity in test area [T] and the fluorescence intensity in control area [C] on test strip card) was defined as 1 U/L, and this was set as the cut‐off value. Blinding reported: Not stated Threshold predefined: No, in the present primary experiment, 200 samples obtained from healthy controls were detected to determine the cut‐off value.
Target condition and reference standard(s)	Reference standard: [1] Clinically defined, criteria not described Possibly RNA test and CT image [3] RNA test and characteristic CT image Samples used: Not stated Timing of reference standard: Not stated Blinded to index test: [1] Yes, prior [3] Not stated Incorporated index test: No Definition of non‐COVID cases: [2] Not stated, none Samples used: Not stated Timing of reference standard: Not stated Blinded to index test: [2] yes, prior [3] Not stated 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: yes (9 samples collected in first two weeks not included in review) Uninterpretable results: Not stated Indeterminate results: Not stated Unit of analysis: Samples
Comparative
Notes	Funding: This work was supported by the Beijing Science and Technology Planning Project. Publication status: Published paper Source: Emerging Microbes and Infections Author COI: XXL and ZJP are employees of Beijing Diagreat Biotechnology, the commercial manufacturer of the test strips.
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?	No
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?			Unclear
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?	No
Were results presented per patient?	No
Could the patient flow have introduced bias?		High risk