Na 2019.

Study characteristics
Patient Sampling	Inclusion/exclusion criteria Inclusion criteria: FFPE specimens of primary diffuse glioma Prior testing Histopathological diagnosis according to WHO 2016 classification and the update series of the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy‐Not Official WHO (cIMPACT‐NOW). Quote: "Ancillary tests used in initial diagnosis included IDH1 (R132H), p53, and ATRX immunostaining and fluorescence in situ hybridization (FISH)‐based detection of 1p/19q‐codeletion. Select cases were immunostained by BRAF (VE1) or by paired set of H3.3K27M and H3K27me3 (midline location). After diagnosis, most representative FFPE specimens were tested for TERT mutation, MGMT methylation, and analyzed by NGS".
Patient characteristics and setting	Number of participants/tumours with results for 1p/19q status by ≥ 2 DNA‐based tests: 135 Country: Republic of Korea Population source and setting: Severance Hospital, Republic of Korea. March 2017 to May 2018 Agea: mean: 51.0 years, standard deviation: 16.3 years Gender: 59.3% male Karnofsky performance status: NR First diagnosis/recurrent disease: unclear. Described as "primary" diffuse gliomas. aThere are 5 participants aged < 18 years in this analysis. We have not excluded them as we are unable to link their individual patient data to the 1p/19q result for all of the tumours.
Index tests	2 tests: FISH and NGS FISH Tumour sample type: FFPE Region(s) analysed: 1p36/1q25, 19q13/19p13 (Vysis, Abbott Molecular, Illinois, USA) Cut‐off: deletion was defined as signal ratios of > 50% for region of interest to control probe. NGS Tumour sample type: FFPE Region(s) analysed: 1p: NRAS, MYCL1; 19q: ERCC1, ERCC2, AKT2 Cut‐off: quote: "The genes with lower than 0.7‐fold change relative to average levels were considered to exhibit significant copy number loss". Additional details: Illumina TruSight Tumor 170 (TST‐170) panel
Target condition and reference standard(s)	Target condition was absolute 1p/19q deletion. FISH used as reference standard in some of our analyses.
Flow and timing	We presumed that both tests were performed on the same sample for each case.
Comparative
Notes
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?	Yes
Did the study avoid inappropriate exclusions?	Yes
Could the selection of patients have introduced bias?		Unclear risk
Are there concerns that the included patients and setting do not match the review question?			Low concern
DOMAIN 2: Index Test (NanoString)
DOMAIN 2: Index Test (aCGH)
DOMAIN 2: Index Test (NGS)
If a threshold was used, was it pre‐specified?	Unclear
Were the index test results interpreted without knowledge of the results of the other tests being compared?	Unclear
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 2: Index Test (G‐banding)
DOMAIN 2: Index Test (FISH (variant 4))
DOMAIN 2: Index Test (SNP array)
DOMAIN 2: Index Test (PCR (with comparison to normal DNA))
DOMAIN 2: Index Test (PCR (without comparison to normal DNA))
DOMAIN 2: Index Test (CISH)
DOMAIN 2: Index Test (MS)
DOMAIN 2: Index Test (RFLP)
DOMAIN 2: Index Test (PCR‐based LOH)
DOMAIN 2: Index Test (NGS or aCGH (or both))
DOMAIN 2: Index Test (Methylation array)
DOMAIN 2: Index Test (FISH)
If a threshold was used, was it pre‐specified?	Yes
Were the index test results interpreted without knowledge of the results of the other tests being compared?	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?			Low concern
DOMAIN 2: Index Test (FISH (variant 1))
DOMAIN 2: Index Test (FISH (variant 2))
DOMAIN 2: Index Test (FISH (variant 3))
DOMAIN 2: Index Test (Real‐time PCR)
DOMAIN 2: Index Test (MLPA)
DOMAIN 2: Index Test (CGH)
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	No
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?			Low concern
DOMAIN 4: Flow and Timing
Was there an appropriate interval between index test and reference standard?	Yes
Were all patients included in the analysis?	Yes
Could the patient flow have introduced bias?		Low risk