Knapskog 2018.

Study characteristics
Patient Sampling	A cross‐sectional study at the memory clinic at Oslo University Hospital, Ullevaal, Norway. 205 patients were referred for diagnostic work‐up between January 2009 and July 2014. 138 participants had a diagnosis of ADD, and 17 were "other dementia". Separate data were available for the performance of biomarkers in distinguishing between ADD from FTD. We did not include data on performance of the index test to discriminate AD participants from MCI or subjective cognitive impairment. Sampling procedure: not reported. Inclusion criteria: CSF biomarkers available. Exclusion criteria: none.
Patient characteristics and setting	Participants underwent clinical history, neuropsychological examination, laboratory tests, neuroimaging. Consensus diagnosis was made by two experienced physicians. Sex: 46.3% of the total sample were female. Age mean (SD): 84.8 ±8.8 for the total sample. MMSE: 23.5 ± 4.1 for ADD; 24.3 ± 3.6 for other dementia. MMSE score was significantly lower in ADD compared to FTD. Disease duration (y): not specified. Sources of recruitment: outpatient memory clinic at the Oslo University Hospital, Ullevall, Norway.
Index tests	Patients gave CSF samples. The samples were collected in polypropylene tubes, centrifuged, aliquoted, and stored at ‐20°C and analysed (within 1 day). Abeta42 was measured using enzyme‐linked immunosorbent assays, obtained from Innogenetics NV, Gent, Belgium. Threshold: pre‐specified at >550 ng/L and >700 ng/L. Were the index test results reported without knowledge of the reference standard? [Unclear]
Target condition and reference standard(s)	Target condition: Alzheimer's disease (differential diagnosis ADD from other dementia) Reference standards: no diagnostic criteria specified; by consensus between two experiences physicians. Physicians were blinded to the results of the index test.
Flow and timing	Data were provided by the author upon request. AD vs FTD (n=71) AD=59; FTD=12; Sensitivity=43%; Specificity=35% (Table 2, p381) TP=25; FP=8; FN=34; TN=4 (calculated in RevMan5) Missing data: Yes. The interval between established clinical diagnosis and CSF sample collection was not reported.
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?	Unclear
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 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	Yes
Were the reference standard results interpreted without knowledge of the results of the index tests?	Yes
Could the reference standard, its conduct, or its interpretation have introduced bias?		Low 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?	Unclear
Were all patients included in the analysis?	Yes
Could the patient flow have introduced bias?		Unclear risk