Jacobs 2001.

Study characteristics
Patient sampling	All patients with right lower quadrant pain in whom a CT examination was requested to evaluate for acute appendicitis were asked to participate Exclusion criteria: prior appendectomy, Crohn's disease, inability to receive oral or intravenous contrast material Recruitment period: August 1997 to April 1999 Included patients initially had focused CT of the lower abdomen with oral contrast material. Immediately thereafter, an intravenous contrast enhanced CT‐scan of the entire abdomen and pelvis was performed
Patient characteristics and setting	Age range (mean): 13 to 87 years (32). The proportion of patients younger than 15 years of age is not reported. 64% women Department of Radiology, Philadelphia, Pennsylvania, USA. Single‐centre study Disease spectrum: unclear
Index tests	Included patients initially had focused CT of the lower abdomen with oral contrast material. Immediately thereafter, an intravenous contrast enhanced CT‐scan of the entire abdomen and pelvis was performed. Hence, each patient was examined with 2 different CT‐protocols CT examination was performed with single‐slice CT‐scanners (CTi or HiSpeed Advantage; General Electric Medical Systems) Slice thickness: 5 mm. Slice interval and voltage: not stated. mAs product: 200 to 220
Target condition and reference standard(s)	Appendicitis. The reference standard had 2 components: intraoperative findings in patients who had surgery, and follow‐up in patients who did not have surgery. What follow‐up consisted of is not reported
Flow and timing	228 patients were included; all were examined with both CT‐protocols. 58 patients had surgery; 152 had clinical follow‐up. 18 patients were lost to follow‐up and were excluded from the analyses, hence 210 patients were included in the analyses. 51 patients had appendicitis
Comparative
Criteria for CT diagnosis of appendicitis	Appendix diameter > 6 mm, abscess or phlegmon in the right iliac fossa, appendicolith, periappendiceal fat stranding, appendix wall enhancement, thickened appendix wall The radiologist graded the likelihood of appendicitis on a 5‐point scale. 1: definitely absent, 2: probably absent, 3: indeterminate, 4: probably present, 5: definitely present. In the accuracy analyses, patients with grade 4 or 5 likelihood of appendicitis were considered CT‐positive
Assessors of the CT‐scan	3 radiologists with varying experience (20 years, 3 years, and 1 month after American Board of Radiology certification) examined both CT‐scans from all patients. In the meta‐analyses, average values of sensitivity and specificity across the 3 radiologists were used to generate 2×2 tables
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
Did the study avoid inappropriate exclusions?	Unclear
Does the study population represent an unselected sample of adults with suspected appendicitis?	Unclear
		Unclear	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?	No
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?	Unclear
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?	No
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?	No
		High