Ong 2020 [A].

Study characteristics
Patient Sampling	Purpose: To evaluate flow immunochromatographic assays and an ELISA test for diagnosing COVID‐19. A small pilot study tested sensitivity and specificity of 6 rapid tests, after which the most sensitive was selected for evaluation in a larger cohort, alongside the ELISA test. 3‐group study to estimate sensitivity and specificity for diagnosis of active disease Design: [1] COVID‐19‐positive patients presenting to a teaching hospital with respiratory symptoms that were suspected for respiratory tract infection (N = 99) [2] COVID‐19‐negative patients presenting to a teaching hospital with respiratory symptoms that were suspected for respiratory tract infection (N = 129) [3] randomly selected historical patient control sera (N = 50) Recruitment: consecutive patients presenting to a teaching hospital for prospective patients. No informed consent because tests were performed on samples that had been acquired for routine clinical care. Unclear for historical patient controls ("randomly selected") and retrospective cohort ("selected") Prospective or retrospective: Prospective (6th to 10th April 2020, n = 117) and retrospective (16th to 29th March 2020, n = 117, and September 2019, n = 50) Sample size: 278 (99) Further detail: had respiratory symptoms that were suspected for respiratory tract infection Unclear for historical patient controls ("adult patients in September 2019")
Patient characteristics and setting	Setting: Hospital A&E Location: A teaching hospital in the Netherlands Country: Netherlands Dates: 17 March 2020 to 10 April 2020 Symptoms and severity: 16/99 (16%) admitted to the ICU within 24 hours Total cohort (COVID +/‐) symptoms (from Supplementary materials): Coughing 68% Dyspnoea 59% Sore throat 17% Rhinorrhoea 15% Fever 48% Demographics: Not reported per group. Whole cohort (positive and negative, n = 228); median age of 61 years (interquartile range (IQR) 46‐74 years), 117 (52%) were male Exposure history: Not stated Non‐Covid group 1: [2] COVID suspects, reference standard‐negative Source: Same hospital as COVID cases, 17 March 2020 to 10 April 2020 Characteristics: Not reported per group. Whole cohort (positive and negative, n = 228); median age of 61 years (interquartile range (IQR) 46‐74 years), 117 (52%) were male Non‐Covid group 2: [3] Pre‐pandemic historic controls Source: September 2019 Characteristics: Adult patients
Index tests	Test name: [A] Orient Gene Biotech COVID‐19 IgG/IgM Rapid Test Cassette [B] Wantai SARS‐CoV‐2 Ab ELISA kit Manufacturer: [A] Orient Gene Biotech [B] Wantai Antibody: [A] IgG/IgM [B] Total antibody Antigen target: [A] Not stated [B] Not stated Evaluation setting: [A] POC, used in laboratory [B] Laboratory, used in laboratory Test method: [A] Lateral flow immunochromatographic assay [B] ELISA Timing of samples: At same time as nasopharyngeal samples. Median time from symptom onset to sample collection was 7 days (IQR 4‐14 days) for all 228 (positive and negative) patients. < 7 days: 39/99 cases 7+ days: 52/99 cases 14+ days: 14/99 cases 7‐13 days: 38/99 cases Unclear: 8/99 cases Timing of samples: At same time as nasopharyngeal samples. Median time from symptom onset to sample collection was 7 days (IQR 4‐14 days) for all 228 (positive and negative) patients. < 7 days: 39/99 cases 7+ days: 52/99 cases 14+ days: 14/99 cases 7‐13 days: 38/99 cases Unclear: 8/99 cases Samples used: [1] and [2] plasma samples [3] Serum Test operator: [A] Laboratory personnel [B] Laboratory personnel Definition of test positivity: [A] Any visible band for IgG, IgM or unspecified immunoglobulin was indicative for a positive result. [B] Not stated (interpreted according to the manufacturer's instructions) Blinding reported: Both clinical information and reference standard results were unavailable to the performers of LFAs and the ELISA. Threshold predefined: [A] Visual [B] interpreted according to the manufacturer's instructions
Target condition and reference standard(s)	Reference standard: PCR (referred to as PCR in Supplementary materials and as NAT in paper): Nucleic acid amplification tests performed according to the national reference method that was established after international collaboration, or by the CE‐IVD kit Gene‐ FinderTM COVID‐19 Plus RealAmp Kit using the Sample to Result Platform ELITe InGenius®. Samples used: Samples were taken from the oral cavity and subsequently from the nasal cavity using the same nasopharyngeal swab. In some cases, sputum samples were tested, because of persisting clinical suspicion of COVID‐19 despite a negative NAT on nasopharyngeal swabs. Timing of reference standard: Median time from symptom onset to sample collection was 7 days (IQR 4‐14 days) for all 228 (positive and negative) patients. < 7 days: 39/99 cases 7+ days: 52/99 cases 14+ days: 14/99 cases 7‐13 days: 38/99 cases Unclear: 8/99 cases Blinded to index test: Not stated Incorporated index test: No Definition of non‐COVID cases: [2] COVID suspects = same nucleic test as COVID cases Nucleic acid amplification tests performed according to the national reference method that was established after international collaboration, or by the CE‐IVD kit Gene‐ FinderTM COVID‐19 Plus RealAmp Kit using the Sample to Result Platform ELITe InGenius®. [3] Historic controls = pre‐pandemic Samples used: [2] COVID suspects = nasopharyngeal swab Samples were taken from the oral cavity and subsequently from the nasal cavity using the same nasopharyngeal swab. In some cases, sputum samples were tested, because of persisting clinical suspicion of COVID‐19 despite a negative NAT on nasopharyngeal swabs. [3] Historic controls = pre‐pandemic Timing of reference standard: [2] COVID suspects = Median time from symptom onset to sample collection was 7 days (IQR 4‐14 days) for all 228 (positive and negative) patients. < 7 days: 40/129 cases 7+ days: 50/129 cases 14+ days: 32/129 cases 7‐13 days: 18/129 cases Unclear: 39/129 cases [3] Historic controls = pre‐pandemic Blinded to index test: [2] Not stated [3] Yes (pre‐pandemic) Incorporated index test: No
Flow and timing	Time interval between index and reference tests: [1] and [2] none ‐ "plasma samples obtained upon hospital presentation, which corresponded to the dates of molecular testing." [3] Pre‐pandemic samples All patients received same reference standard: Yes (cohort), No (historic controls) Missing data: 5/228 samples were unavailable for ELISA. In some patients, time from symptom onset was undetermined or unavailable. Uninterpretable results: Not stated Indeterminate results: Not stated Unit of analysis: Patients
Comparative
Notes	Funding: No funding Publication status: Published paper Source: Clinical Microbiology and Infection Author COI: The authors declared 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?	Yes
If a threshold was used, was it pre‐specified?	Yes
Could the conduct or interpretation of the index test have introduced bias?		Low 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?	Yes
Did all participants receive a reference standard?	No
Were results presented per patient?	Yes
Could the patient flow have introduced bias?		High risk