Validation of the Pediatric Advanced Weight Prediction in the Emergency Room Extra Large Mid-Arm Circumference scale in Turkish children

Aim This study aimed to validate the Pediatric Advanced Weight Prediction in the Emergency Room Extra Large-Mid-Arm Circumference (PAWPER XL-MAC) weight estimation scale in Turkish children by evaluating its accuracy, agreement, and validity across age groups. We assessed the scale's performance using mid-arm circumference (MAC), habitus status (HS), and height to predict weight, while examining age- and gender-related differences. Methods This study included pediatric patients (aged 0–18 years) who presented to a pediatric surgery outpatient clinic from December 2024 to April 2025. Data on demographics, height, weight, MAC, and clinician-assigned HS (1–7) were collected. PAWPER XL-MAC estimated weights were calculated. Accuracy was assessed using percentage within 10% (PW10) and percentage within 20% (PW20). Analyses included descriptive stats, Pearson correlations, t -tests/Welch's t -tests, ANOVA, multiple regression, Bland–Altman plots, and confirmatory factor analysis (CFA) for validity measures. SPSS, R, and Jamovi were used. Results The cohort comprised 323 boys (65.8%) and 168 girls (34.2%), for a total of 491 patients, with infants (0–2 years) forming the largest group (41.8%). Significant gender differences were observed in MAC and weight ( p < 0.01). The multiple linear regression model (weight∼MAC + height + HS) demonstrated a strong fit (R 2 = 0.878). Overall, PW10 was 10.8%, and PW20 was 21.0%, with marked age-dependent variation, with moderate performance in schoolers (PW10: 10.1%, PW20: 22.2%) and the highest in adolescents (PW10: 41.9%, PW20: 81.7%). MAC–HS agreement showed a moderate-to-weak positive association (gamma = 0.226). PCA revealed a single dominant factor explaining 62.4% of variance, with strong loadings for weight (0.89) and MAC (0.85). CFA proxy indices indicated acceptable-to-good model fit (comparative fit index ∼0.92–0.95, standardized root mean square residual ∼0.06–0.08). Conclusion The PAWPER XL-MAC scale shows acceptable structure validity in Turkish children but has age-related accuracy issues, especially in younger groups. Age-specific adjustments are recommended to improve reliability for emergency weight estimation and drug dosing in children.