Medical calculator
Modified Alvarado Score (MAS) for Acute Appendicitis
Widely used in emergency medicine and pediatric surgery to predict acute appendicitis probability. Composed of 7 items (symptoms, signs, leukocytosis >10,000/μL) with a total score of 9 points and diagnostic accuracy of 94.35%.
Select patient symptoms, physical exam signs, and WBC lab result to calculate the Modified Alvarado Score.
1. Symptoms (3 Points)
Evaluate patient clinical symptoms
Migratory Right Iliac Fossa Pain
Pain starting periumbilically/epigastrically and migrating to RIF
Anorexia
Loss of appetite or reduced oral intake
Nausea / Vomiting
Presence of nausea or emesis
2. Physical Exam Signs (4 Points)
Evaluate abdominal exam signs and body temperature
Right Iliac Fossa Pain / Tenderness
Tenderness on palpation at McBurney's point or RIF
Rebound Tenderness in RIF
Pain on rapid release of deep abdominal pressure in RIF
Elevated Temperature (> 37.5 °C)
Body temperature > 37.5 °C
3. Laboratory Investigation (2 Points)
Evaluate white blood cell count
Leukocytosis (> 10,000 WBC / μL)
WBC count > 10.0 × 10⁹/L