Platon 2009.

Study characteristics
Patient sampling	Consecutive adult (> 18 years) patients with suspected appendicitis presented to the Emergency Department during the daytime. Pregnant women were excluded
Patient characteristics and setting	Age range (median): 18 to 96 years (42.5); 52% women. Pregnant women were excluded Emergency Department in Geneva, Switzerland. Single‐centre study Disease spectrum: any suspicion of appendicitis
Index tests	4‐slice CT of the entire abdomen (MX8000, Philips Medical Systems). Slice thickness: 5 mm. Slice interval: not stated. Voltage: 120 kV 2 CT‐protocols were compared: Standard dose: tube current time product: 180 mAs. Enhancement by oral and intravenous contrast Low dose: tube current time product: 30 mAs. Enhancement by oral contrast For the low‐dose protocol, effective doses were 1.2 ± 0.1 mSv for men; 1.7 ± 0.2 mSv for women
Target condition and reference standard(s)	Appendicitis was approached by intraoperative assessment. The proportions of patients with surgery and follow‐up as reference standards are not stated. Follow‐up consisted of recoding the definitive diagnosis in the discharge report
Flow and timing	86 patients were included in the study and in the analyses
Comparative
Criteria for CT diagnosis of appendicitis	CT diagnosis of appendicitis was based on the following findings: appendix diameter > 6 mm, periappendiceal fat stranding, appendicolith, periappendiceal flegmone or abscess, periappendiceal free fluid, caecal wall thickening, arrowhead sign The relative importance and the logical combination of these findings are not stated Appendicitis was excluded when gas or contrast medium was depicted in the appendix lumen
Assessors of the CT‐scan	Paired assessments by 2 experienced, board certified radiologists. Disagreements between radiologists were resolved by discussion
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
Did the study avoid inappropriate exclusions?	Yes
Does the study population represent an unselected sample of adults with suspected appendicitis?	Unclear
		Low	Unclear
DOMAIN 2: Index Test All tests
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?	Yes
Is the index test described in sufficient detail to permit its replication?	Yes
Was the analysis based on the initial evaluation of the CT‐scan by the radiologist on call?	No
		Low	High
DOMAIN 3: Reference Standard
Is the reference standards likely to correctly classify the target condition?	No
Were the reference standard results interpreted without knowledge of the results of the index tests?	No
		High	Low
DOMAIN 4: Flow and Timing
Did all patients receive a reference standard?	Yes
Did all patients receive the same reference standard?	No
Did all patients with a positive CT‐scan have surgery?	Unclear
Did all patients with a negative CT‐scan have clinical follow‐up?	Unclear
Was the choice of reference standard independent of the result of the index test?	No
Were all patients included in the analyses?	Yes
		High