Introduction: Acute appendicitis is one of the commonest emergency presenting at general surgery department calling for an emergency appendectomy either by open laparotomy or laparoscopic technique is performed. Thus a rapid yet accurate diagnosis becomes important to prevent wrong procedure.

Objectives: We intend to compare the diagnostic accuracy of Modified Alvarado Score System (MASS) and ultrasound in the diagnosis of acute appendicitis at our institution in Dakshina kannada.

Materials and methods: A prospective study was conducted between October 2015 to October 2017 at our institution. 100 patients were included in the study after obtaining an informed consent. A detailed clinical examination was performed following which the clinical finding and laboratory findings including total leucocyte count and differential count were in noted in the patient’s study proforma. Patients were then subjected to ultrasound examination for appendicitis. The radiological findings were also then tabulated. Appendectomy was then performed followed by histopathological examination of the specimen for  confirmation of the diagnosis. The histopathological diagnosis of acute appendicitis was considered as positive report and using SPSS software and MEDCALC Software descriptive statistics were calculated for MASS and ultrasound.

Results: Out of 100 patients 52 were males and 48 were females. MASS and ultrasound showed sensitivity, specificity, positive predictive value and negative predictive value of 60%, 90%, 98.18%, 20%, 93.3%, 20%, 91.3%, and 25% respectively. Application of Chi­square test showed that MASS had better correlation histopathological finding with a statistically significant p value of 0.000 (< 0.005).

Conclusion: Both MASS and Ultrasound examination  have a distinct advantage and limitation when used independently. But utilisation of both modalities complementarily serves as a better management strategy in acute appendicitis.

Keywords: MASS; Ultrasound; Sensitivity; Specificity; p value; Complementary Value.