Background Acute appendicitis remains difficult-to-diagnose in spite of being a common acute abdominal condition. Early and correct diagnosis is essential either to proceed with early appendectomy or conservative approach so that complications and negative explorations can be minimised. Scoring systems can help in quick diagnosis and decision making. Though the Alvarado scoring is the widely used system, differences in diagnostic accuracy have been observed when it is applied to varied populations. Materials and methods The objective was to find the predictive accuracy of Modified Alvarado score, Appendicitis Inflammatory Response score and Raja Isteri Pengiran Anak Saleha Appendicitis score, in a diagnostic test evaluation study. From first January 2018 to first January 2019, 107 consecutive patients admitted with a diagnosis of suspected appendicitis were assessed with these scores. Sensitivity, specificity, positive and negative predictive value, positive and negative likelihood ratio and area under curve were determined for each. Results Negative appendicectomy rate was 15.89%. Sensitivity, specificity, positive predictive value, negative predictive value and diagnostic accuracy were 64.44%, 58.82%, 89.23%, 23.81% and 63.55% respectively for Modified Alvarado; 97.78%, 29.41%, 88%, 71.43% and 86.92% respectively for Appendicitis Inflammatory Response; 87.78%, 76.47%, 95.18%, 54.17% and 85.98% respectively for Raja Isteri Pengiran Anak Saleha Appendicitis. Area under the curve was 0.726797 for Modified Alvarado, 0.946732 for Appendicitis Inflammatory Response and 0.910131 for Raja Isteri Pengiran Anak Saleha Appendicitis . Conclusion Appendicitis Inflammatory Response score probably is superior to Alvarado in the paediatric population because the variables scored are easy to apply to children, while Alvarado requires children to identify subjective symptoms which may not always be accurate. Appendicitis Inflammatory Response and Raja Isteri Pengiran Anak Saleha Appendicitis are better diagnostic scoring system for acute appendicitis than Modified Alvarado. Also, both these scores can be easily calculated by complete history, detailed clinical examination and basic laboratory investigations.