Saitta 2017.

Study characteristics
Patient Sampling	90 cirrhotic patients who had evidence of liver nodule(s) at US examination for the first time and who consecutively attended the liver unit of the University Hospital of Messina from November 2011 to October 2013 were enrolled. All of them underwent blood sampling within 1 week before or after the US identification of liver nodules, and the corresponding serum samples were aliquoted and stored at 80°C until testing. Age range: 52‐79. Males 72%
Patient characteristics and setting
Index tests	AFP: AFP serum levels were measured on a Lumipulse G1200 (Fujirebio Inc.), using the LUMIPULSE G AFP‐N kit (Fujirebio Tokyo, Japan), respectively, according to the manufacturer’s instructions. All tests were performed in duplicate. To determine the optimal cut‐off value for PIVKA‐II and AFP in the diagnosis of HCC, receiver operating characteristic curves were constructed using all possible cut‐offs for each assay. Receiver‐operating characteristic curves were plotted to identify PIVKA‐II and AFP cut‐off values that would best distinguish cirrhotic patients with HCC nodules from patients with regenerative/dysplastic nodules. The optimal cut‐off was 60 mAU/mL for PIVKA‐II and 6.5ng/mL for AFP.
Target condition and reference standard(s)	All patients were followed up for at least 18 months after US nodule (s) detection through imaging techniques – contrast‐enhanced computed tomography and/or magnetic resonance imaging – and/or nodule needle biopsy performed according to the American Association for the Study of Liver Disease guidelines for HCC management.
Flow and timing	No information on interval between index test and reference standard
Comparative
Notes	"The authors have no funding and conflicts of interest 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?	Yes
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 2: Index Test (AFP)
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?	No
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?	No
Were all patients included in the analysis?	Yes
Could the patient flow have introduced bias?		High risk