Identification of Children With a Positive Ultrasound and Appendicitis Using the Pediatric Appendicitis Risk Calculator: Retrospective Cohort Study
Bibliographic record
Abstract
OBJECTIVES: Up to 10% of positive ultrasounds (US) for suspected pediatric appendicitis are false positive. Minimizing the negative appendectomy rate is gaining importance as a quality indicator, with a proposed benchmark of < 2%. The validated Pediatric Appendicitis Risk Calculator (pARC) score [range 0%-100%] used alone identifies the entire appendicitis risk spectrum, whereas the optimal surgical candidates should be at a very high risk. Therefore, pARC risk stratification in conjunction with positive US may be useful to identify the best surgical candidates. The primary objective was to determine the proportion of children with positive US plus medium-high risk pARC ≥ 25% with appendicitis. HYPOTHESIS: We hypothesized this proportion would be 98%, with lower 95% CI ≥ 96%. METHODS: A retrospective cohort study of 327 previously healthy children 4-17 years old at a pediatric ED with suspected appendicitis and positive US interpretations. Four investigators abstracted demographic, clinical, and imaging data. pARC includes seven demographic, clinical, and laboratory variables and is quantified according to the published formula. The primary outcome was appendicitis, based on pathology. All non-operated patients underwent a follow-up to exclude missed appendicitis. RESULTS: A total of 294/327 (89.9%) patients with positive US had pathology-proven appendicitis, and 33 (10.1%) had no appendicitis; pARC ≥ 25% was assigned to 259/327 (79.2%) patients. In total, 255/259 (98.5%) children with pARC ≥ 25% had pathology-proven appendicitis (95% CI 96.1-99.6) versus 39/68 (57.3%) with pARC < 25%; p < 0.0001. Probability of no appendicitis increased with decreasing pARC cut-offs from 0/230 (0%) for pARC ≥ 40% to 13/284 [4.6% (2.5-7.7)] for pARC ≥ 15%. The pARC ≥ 25% plus positive US combination had sensitivity 86.7% (82.3-90.4), specificity 87.9% (71.8-96.6), positive predictive value 98.5% (96.1-99.6), and negative predictive value 42.6% (30.7-55.2). CONCLUSIONS: In children with suspected appendicitis, a combination of positive US and pARC ≥ 25% carries a very high probability of appendicitis. Children with lower pARCs may be candidates for clinical re-evaluation or further imaging.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.000 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".