Chong 2010 RIPASA score from 15 caller-assigned findings (half-points; max 16). Age <40 scores 1.0, ≥40 scores 0.5; male 1.0, female 0.5; symptoms <48h 1.0, otherwise 0.5. Guarding and Rovsing 2.0 each. Fever, raised WCC, and foreign NRIC are caller-assigned; magent does not apply a °C or WBC cutoff. Derivation ROC: <7.5 below_cutoff, ≥7.5 at_or_above_cutoff. Not a diagnosis or operating-room protocol. magent does not examine the abdomen.

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