Li 2016c.

Study characteristics
Patient Sampling	This study included 435 chronic hepatitis B patients (G1) and 195 pre‐clinical patients (G2) defined as samples longitudinally collected from the same patients as G1, but at an average of 6 months prior to diagnosis. They were divided into 3 cohorts: discovery, training and validation cohort. Data for accuracy of AFP is provided in training and validation cohorts. Inclusion criteria: G1 group: (A) No HCC was diagnosed at least one year after G3 time point; (B) Traditional ultrasound and AFP tests were performed on that patient for cancer screening and the data are available. G2 group: (A) No tumours and chronic diseases unrelated to the liver. (B) Traditional ultrasound and alpha‐fetoprotein (AFP) tests was performed on that patient once every 6 months for HCC screening, and the data are available to allow assessment of sensitivity and specificity for the biomarkers. Age range and % of males not reported
Patient characteristics and setting
Index tests	AFP: AFP cut‐off not pre‐specified. Quote: "The optimal cutoff value was determined by following criteria: A). maximizing the sum of sensitivity and specificity; B). minimizing the overall error (square root of the sum [1‐sensitivity]2+[1‐specificity]2); C). minimizing the distance of the cut‐off value to the top‐left corner of the ROC curve"
Target condition and reference standard(s)	HCC: NCCN guidelines (CT, MRI)
Flow and timing	No information on interval between index test and reference standard
Comparative
Notes	"No conflicts of interest exist. The authors have no financial relationship to disclose."
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	No
Was a case‐control design avoided?	No
Did the study avoid inappropriate exclusions?	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 (AFP)
Were the index test results interpreted without knowledge of the results of the reference standard?	No
If a threshold was used, was it pre‐specified?	Yes
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 (US+AFP)
DOMAIN 2: Index Test (US)
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
Did all patients receive the same reference standard?	Unclear
Were all patients included in the analysis?	Yes
Could the patient flow have introduced bias?		Unclear risk