Becker 2010.

Study characteristics
Patient sampling	Retrospective study
Patient characteristics and setting	Study location: Miami, USA Study period: 2000 to 2005 Care setting: level 1 trauma centre Mass casualty: no Participants enrolled: 3181: 2274 men and 907 women Participants included in analysis: 3181 Age: mean age 39 ± 19 years Type of injury: abdominal trauma Injury severity: ISS 22.9 ± 18 Haemodynamic stability: stable conditions Inclusion criteria: blunt trauma patients who underwent both US as a part of initial assessment and CT scan of the abdomen. Patients were divided into 3 groups according to their ISS: Group 1: ISS 1 to 14; Group 2: ISS 16 to 24; Group 3: ISS ≥ 25 (group allocation is reported as in the published reports ‐ the trialists did not say what happened to patients who had an ISS = 15). Age, gender, mechanism of injury, physiologic parameters, laboratory test results, ISS, radiology reports, and all applied procedures were retrospectively reviewed by the study team. Exclusion criteria: penetrating trauma, no US examination or CT scan
Index tests	Index test: FAST US protocol: trauma team members performed US examinations on all blunt trauma participants in the resuscitation bay. The US was obtained with the participant in supine position by the attending, trauma fellow, or resident. A positive US examination was considered to be a true positive if the CT scan revealed free fluid, and considered to be a false positive if free fluid was not confirmed at the subsequent CT scan. Negative US findings were counted as true negatives if the CT scan was negative and the participant had an uneventful course, and considered to be a false negative if the participant had a negative US and positive CT examination or was operated on and felt to have a therapeutic laparotomy. Hardware used: Aloka SSD 1000 (Aloka Co Ltd, Wallingford, CT) with a 3.5‐MHz curved probe Description of imaging technique: 4 areas were examined: perihepatic, perisplenic, pelvic, and pericardial
Target condition and reference standard(s)	Target condition: free fluid Reference standard: CT (CT technique not specified), laparotomy Description of technique: not reported
Flow and timing	Time between US and reference standard: not reported
Comparative
Notes
Methodological quality
Item	Authors' judgement	Risk of bias	Applicability concerns
DOMAIN 1: Patient Selection
Was a consecutive or random sample of patients enrolled?	No
Did the study avoid inappropriate exclusions?	Yes
		Unclear	Low
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
Was the qualification of the US operator appropriate?	Unclear
Was the US hardware (i.e. generation, manufacturer, probe, etc.) up to date?	Yes
Was the US protocol (i.e. 'classic' FAST) appropriate?	Yes
Are there concerns that the definition or performance of the index test (i.e. POC US of trauma) do not match generally accepted, established, or practiced rules or recommendations?	No
		Low	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
Was the qualification of the doctors (i.e. radiologists, surgeons, etc.) determining the reference standard appropriate?	Unclear
Was the reference imaging standard (i.e. MDCT‐rows (4 to ≥ 256 slices), contrast‐imaging, etc.) up to date?	Yes
Are there concerns that the definition or performance of the reference tests (e.g. CT, MRI, laparatomy, thoracotomy, autopsy, etc.) do not match generally accepted, established, or practiced rules or recommendations?	Unclear
		Unclear	Unclear
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
Did all participants receive a reference standard? (Risk of partial verification bias)	Yes
		Unclear