Fenton 1989.

Study characteristics
Patient sampling	Type of study: retrospective study. Consecutive or random sample: unclear.
Patient characteristics and setting	Sample size: 156. Females: not stated. Age: not stated. Presentation: Inclusion criteria: People with histological confirmation of acute cholecystitis. Setting: Department of Surgery, USA.
Index tests	Index test: intraoperative cholangiography. Further details: Technical specifications: not applicable. Performed by: surgeon. Criteria for positive diagnosis: filling defect.
Target condition and reference standard(s)	Target condition: common bile duct stones. Reference standard: extraction of stones in people with positive intraoperative cholangiography and clinical follow‐up of minimum 12 months in people with negative intraoperative cholangiography. Further details: Technical specifications: not applicable. Performed by: surgeons and clinicians. Criteria for positive diagnosis: extraction of stones in people with positive intraoperative cholangiography and clinical follow‐up of minimum 12 months in people with negative intraoperative cholangiography.
Flow and timing	Number of indeterminates for whom the results of reference standard was available: not stated. Number of participants who were excluded from the analysis: 15 (8.8%).
Comparative
Notes	Attempted to contact the authors in June 2013. Received no replies.
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
		High	High
DOMAIN 2: Index Test IOC
Were the index test results interpreted without knowledge of the results of the reference standard?	Unclear
		High	Low
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?	Unclear
		High	High
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?	No
		High