Blunt Intra-Abdominal Injury: Likelihood Ratios

History and Physical

| | Positive LR | Negative LR | | --------------------------------- | -------------- | ----------------- | | Coastal margin tenderness | 1.4 [1.3-1.7] | 0.74 [0.66-0.84] | | Abdominal tenderness on exam | 1.4 [1.3-1.5] | 0.61 [0.46-0.80] | | Abdominal pain complaint | 1.6 [1.3-2.0] | 0.52 [0.34-0.79] | | Abdominal guarding | 3.7 [2.3-5.9] | 0.80 [0.70-0.91] | | Abdominal distention | 3.8 [1.9-7.6] | 0.90 [0.83-0.98] | | Abdominal "seat belt sign" in MVC | 5.6-9.9 | 0.53-0.55 | | Glasgow coma scale < 14 | 1.8-2.0 | 0.86-0.87 | | Presence of femur fracture | 2.9 [2.1-4.1] | 0.92 [0.88-0.96] |

Lab Tests

| | Positive LR | Negative LR | | -------------------------- | ---------------- | ----------------- | | Hematocrit change > 5% | 0.91 [0.44-1.9] | 1.0 [0.79-1.4] | | Serum lactate > 2.2 mmol/L | 1.3 [1.1-1.5] | 0.61 [0.41-0.90] | | Serum WBC > 10K | 1.7 [1.5-2.0] | 0.35 [0.23-0.55] | | Hematocrit < 36% | 2.2 [1.6-3.1] | 0.76 [0.64-0.90] | | Hematocrit < 30% | 3.3 [2.4-4.5] | 0.79 [0.71-0.88] | | AST > 50 U/L | 2.5 [2.0-3.0] | 0.38 [0.26-0.56] | | AST or ALT > 130 U/L | 5.2 [3.5-7.9] | 0.46 [0.33-0.65] | | Hematuria > 50 RBC/hpf | 3.7 [2.4-5.8] | 0.44 [0.35-0.77] | | Hematuria | 4.1 [3.4-4.9] | 0.66 [0.60-0.24] | | Base deficit < -6 mEq/L | 18 [11-30] | 0.12 [0.06-0.24] |

Imaging

| | Positive LR | Negative LR | | --------------------- | --------------- | ----------------- | | Abdominal pelvic Xray | 1.6 [0.78-3.4] | 0.96 [0.90-1.0] | | Abdominal pelvic Xray | 2.5-3.8 | 0.70-0.96 | | FAST ultrasound | 30 [20-46] | 0.26 [0.19-0.34] |

References

• Nishijima DK et al. Does this adult patient have a blunt intra-abdominal injury? JAMA 2012;307(14):1517-27 [PubMed]