Pediatric Surgery Research Collaborative (PedSRC) Rule for Blunt Abdominal Trauma

PedSRC blunt abdominal trauma calculator: five binary criteria (AST >200, abdominal wall trauma or distension or tenderness, abnormal chest X-ray, abdominal pain, abnormal amylase or lipase). Score 0 to 5; score 0 marks the very low risk cohort.

PedSRC rule for blunt abdominal trauma

After blunt abdominal trauma, mark each PedSRC criterion that is present. Each positive finding adds 1 point. A total score of 0 identifies the PedSRC very low risk cohort. Stabilize the patient and reassess as new data arrive.

Criteria (each yes = +1)

Disclaimer: The PedSRC rule is an educational adjunct for blunt abdominal trauma in children. It does not replace resuscitation, serial examination, institutional pathways, or clinician judgment. Imaging decisions must integrate mechanism, hemodynamics, laboratory trends, and caregiver follow-up capacity.

PedSRC rule: formula, variables, and context

The Pediatric Surgery Research Collaborative (PedSRC) rule is a five-item, additive score for children with blunt abdominal trauma. Each item is worth 1 point if present. The total score ranges from 0 to 5. A score of 0 defines a very low risk cohort in which important intra-abdominal injury was uncommon in validation samples, so abdominal CT is often optional when the overall clinical picture and observation plan support that approach.

The five variables

AST >200 U/L (serum aspartate aminotransferase).
Abdominal wall trauma, distension, or tenderness on physical examination.
Abnormal chest X-ray (interpreted as abnormal in the trauma evaluation).
Complaint of abdominal pain.
Abnormal amylase or lipase (pancreatic enzymes interpreted as abnormal per local laboratory standards).

Scoring

PedSRC score = number of criteria present (0 to 5). Very low risk is defined as score 0 (no criteria present). Any positive criterion yields a score of 1 or higher and excludes that very low risk classification.

Relation to other rules

The PECARN pediatric intra-abdominal injury algorithm uses different variables (including Glasgow Coma Scale and several examination findings) and was derived in a separate multicenter cohort. PedSRC uses laboratory and chest radiograph inputs in addition to history and examination. Choose and document which rule you apply so consultants and handoffs remain clear.

Evidence summary

External validation applied the five-variable PedSRC rule to a large public dataset of pediatric blunt abdominal trauma patients with complete predictor data. When no variable was abnormal, sensitivity for intra-abdominal injury and for injury receiving acute intervention was high, with strong negative predictive value in that subgroup. Performance estimates depend on prevalence, protocol-driven testing, and referral patterns at your center.

Clinical use

Prioritize stabilization (airway, breathing, circulation) before imaging decisions.
Use the score to support shared decision-making about ionizing radiation, especially in children.
Obtain abdominal CT when clinical suspicion for significant intra-abdominal injury remains despite a low PedSRC score, or when the examination or vital signs evolve.
Align disposition with observation capacity and the family's ability to return for reassessment.

References

Streck CJ, Vogel AM, Zhang J, et al. Identifying children at very low risk for blunt intra-abdominal injury in whom CT of the abdomen can be avoided safely. J Am Coll Surg. 2017;224(4):449-458. doi:10.1016/j.jamcollsurg.2016.12.041 (PubMed). Prospective derivation by the Pediatric Surgery Research Collaborative (PedSRC), n = 2,188.
Arbra CA, Vogel AM, Plumblee L, et al. External validation of a five-variable clinical prediction rule for identifying children at very low risk for intra-abdominal injury after blunt abdominal trauma. J Trauma Acute Care Surg. 2018;85(1):71-77. doi:10.1097/TA.0000000000001933 (PubMed).
Educational overview: MDCalc: PedSRC Rule for Blunt Abdominal Trauma.

What the PedSRC rule is

The Pediatric Surgery Research Collaborative (PedSRC) blunt abdominal trauma rule is a simple additive clinical prediction score developed from multicenter pediatric trauma research. It combines five readily available historical, examination, laboratory, and imaging signals into a total from 0 to 5. The intended use is to identify a very low risk subgroup of children after blunt abdominal trauma in whom important intra-abdominal injury was uncommon in published derivation and external validation samples, so that decisions about abdominal computed tomography can be individualized together with observation, serial examination, and shared discussion about ionizing radiation.

The rule does not diagnose injury by itself. It structures documentation, supports handoffs, and complements emergency and trauma pathways. Stabilization of airway, breathing, and circulation always precedes imaging triage.

Clinical setting

Blunt abdominal trauma in children arises from falls, handlebar injuries, motor vehicle collisions, assault, sports impacts, and crush mechanisms. Clinicians must balance the morbidity of missed solid organ or hollow viscus injury against the cumulative radiation risk of abdominal CT in young patients. Clinical prediction rules aggregate predictable patterns so teams can explain why imaging may be deferred in selected stable patients with reliable follow-up, and why imaging remains appropriate when any high-risk feature appears.

The five PedSRC criteria

Each criterion is binary. If present, it contributes 1 point. The domains intentionally mix hepatic enzyme release, abdominal surface and palpation findings, thoracic imaging context, patient-reported pain, and pancreatic enzyme abnormalities.

1. Aspartate aminotransferase (AST) greater than 200 U/L

Elevated AST after trauma may reflect hepatic parenchymal stress or injury, muscle injury, hemolysis, or other sources depending on context. The PedSRC derivation used a fixed cutoff greater than 200 U/L within the assessment window applied in the original studies. Laboratories should report values in consistent units; always verify local assay reference ranges when documenting abnormal results.

2. Abdominal wall trauma, distension, or tenderness on examination

This item bundles visible abdominal wall trauma signs, abdominal distension, or tenderness on physical examination. It captures focal examination abnormalities that increase concern for underlying injury even when the child is distracted, frightened, or partially uncooperative.

3. Abnormal chest radiograph

Chest X-ray abnormalities in blunt trauma may include rib fractures, pulmonary contusion, hemothorax, pneumothorax, or related findings depending on mechanism and technique. In PedSRC, the radiograph is interpreted as abnormal in the clinical context of blunt trauma evaluation. Correlation with mechanism and symptoms matters because some abnormalities may be incidental while others imply force vectors that also threaten intra-abdominal structures.

4. Complaint of abdominal pain

Subjective abdominal pain is included because symptom reporting changes with age and developmental stage. Younger children may localize pain poorly; older children and adolescents may describe pain clearly. The criterion is met when the patient reports abdominal pain as solicited in routine trauma assessment.

5. Abnormal amylase or lipase

Elevation of serum amylase or lipase raises concern for pancreatic or duodenal injury after blunt epigastric forces. Laboratories define upper limits of normal differently; this calculator treats enzymes as abnormal when they exceed the local upper reference limit or are otherwise clinically flagged as abnormal.

Scoring and risk interpretation

PedSRC score equals the count of present criteria, ranging from 0 to 5.

Score 0: none of the five criteria are present. This pattern defines the PedSRC very low risk cohort. In external validation, absence of all variables was associated with high sensitivity for excluding important intra-abdominal injury and strong negative predictive value in that subgroup, though performance varies with baseline injury prevalence, imaging thresholds, and transfer patterns.
Score 1 through 5: at least one criterion is present. The patient does not meet the PedSRC very low risk definition. Further evaluation, monitoring, and imaging should follow clinical gestalt, evolving examination, hemodynamics, laboratory trends, and institutional trauma protocols.

The score is not graded beyond the zero versus nonzero split for the primary very low risk label in this implementation. Multiple positive findings increase overall concern even though the displayed risk category remains “not very low” once any single item is positive.

Relation to other pediatric abdominal trauma approaches

The well-known PECARN pediatric intra-abdominal injury clinical framework uses a different variable set (including mental status and additional examination features) and was derived in a separate multicenter network. PedSRC incorporates AST, chest radiograph, and pancreatic enzymes explicitly. Teams should document which rule guided a given encounter so consultants, nursing, and subsequent shifts understand the rationale for imaging or observation.

Limitations and safe use

Clinical judgment overrides any score: Obtain abdominal CT when suspicion for significant injury remains high despite a score of 0, when vital signs or perfusion worsen, when pain escalates, or when new findings appear during observation.
Incomplete data: Missing laboratories or imaging should be addressed rather than assumed normal.
Mechanism severity: High-energy mechanisms or concurrent injuries may warrant imaging even when early screening bloodwork is unrevealing.
Population shift: Validation performance in community settings, transferred patients, or protocol-driven early CT populations may differ from published cohorts.

Medicolegal and documentation notes

This calculator supports education and structured bedside reasoning. It does not establish a standard of care, substitute for trauma center policies, or replace surgeon or emergency physician evaluation. Radiation risk conversations with caregivers remain important whenever CT is considered.

Pediatric Surgery Research Collaborative (PedSRC) Rule for Blunt Abdominal Trauma

PedSRC blunt abdominal trauma calculator: five binary criteria (AST &gt;200, abdominal wall trauma or distension or tenderness, abnormal chest X-ray, abdominal pain, abnormal amylase or lipase). Score 0 to 5; score 0 marks the very low risk cohort.

PedSRC rule for blunt abdominal trauma

Criteria (each yes = +1)

PedSRC blunt abdominal trauma calculator: five binary criteria (AST >200, abdominal wall trauma or distension or tenderness, abnormal chest X-ray, abdominal pain, abnormal amylase or lipase). Score 0 to 5; score 0 marks the very low risk cohort.