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Abstract
Objective: To determine the diagnostic yield and accuracy of focused assessment with sonography for trauma (FAST) for intra-abdominal injury in adults with blunt abdominal trauma, using contrast-enhanced computed tomography (CECT) as the reference standard.
Study Design: Cross-sectional validation study.
Settings: Department of Radiology, Jinnah Postgraduate Medical Centre, Karachi.
Period: Jan 2025 to April 2025.
Material & Methods: This study included 145 adults aged 18-65 years presenting within 24 hours of blunt abdominal trauma and undergoing FAST followed by clinically indicated CECT. Diagnostic performance and true-positive yield were calculated with 95% Wilson confidence intervals (CIs).
Results: The mean age was 37.8 +/- 9.7 years and 118 (81.4%) participants were male. CECT confirmed injury in 71 (49.0%). FAST produced 56 true-positive, 12 false-positive, 62 true-negative and 15 false-negative results. Diagnostic yield was 38.6% (95% CI 31.1%-46.7%); sensitivity 78.9% (68.0%-86.8%); specificity 83.8% (73.8%-90.5%); positive predictive value 82.4% (71.6%-89.6%); negative predictive value 80.5% (70.3%-87.8%); and accuracy 81.4% (74.3%-86.9%). Agreement was substantial (kappa=0.627). Sensitivity was 86.7% in unstable and 76.8% in stable patients.
Conclusion: FAST provided useful bedside triage, but 15 CECT-confirmed injuries were missed. A negative FAST should not replace CECT when the patient is stable or clinical suspicion remains high.