Bigner 1999.

Study characteristics
Patient Sampling	Inclusion/exclusion criteria Inclusion criteria: tumours composed partially or completely of neoplastic oligodendroglia (only cases on which there was agreement between 2 or 3 of the 3 observers for histological classification were included); frozen tissue and normal peripheral lymphocytes available. Prior testing Histopathological classification
Patient characteristics and setting	Number of participants/tumours with results for 1p/19q status by ≥ 2 DNA‐based tests: 53 Country: USA Population source and setting: NR Age: mean: 39.9 years, standard deviation: 11.8 years Gender: 64.2% male Karnofsky performance status: NR First diagnosis/recurrent disease: unclear. We excluded the recurrences for people whose primary tumour was also included in the study. Some additional participants had had prior surgery or RT, unclear if the tumours studied were recurrences.
Index tests	2 tests: CGH and PCR‐based LOH CGH Tumour sample type: frozen Region(s) analysed: genome wide Cut‐off: ratio of 0.85 indicated a loss. PCR Tumour sample type: frozen Region(s) analysed: FGR, MYCL1, AMY2B (1p); D19S217, D19S112, D19S412, STD, D19S596, D19S180, D19S254, D19S218 (19q) Cut‐off: a reduction in intensity > 50% in the tumour lane compared to the corresponding blood lane was scored as LOH.
Target condition and reference standard(s)	Target condition was absolute 1p/19q deletion. PCR‐based LOH used as reference standard in some of our analyses.
Flow and timing	Both tests were performed on frozen tumour material.
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?	Yes
Was a case‐control design avoided?	Yes
Did the study avoid inappropriate exclusions?	Yes
Could the selection of patients have introduced bias?		Low risk
Are there concerns that the included patients and setting do not match the review question?			High
DOMAIN 2: Index Test (NanoString)
DOMAIN 2: Index Test (aCGH)
DOMAIN 2: Index Test (NGS)
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)
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?		Unclear risk
Are there concerns that the index test, its conduct, or interpretation differ from the review question?			Low concern
DOMAIN 2: Index Test (NGS or aCGH (or both))
DOMAIN 2: Index Test (Methylation array)
DOMAIN 2: Index Test (FISH)
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)
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?		Unclear 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?	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