
Background and Objectives: Acute appendicitis is most common surgical emergency and Appendicectomy for same is a common procedure. The rate of negative appendicectomies remains high despite several technical advancements. The study aims to compare few investigations like Total leucocyte count (TLC), C-reactive protien (CRP), Lactate dehydrogenase (LDH) and Ultrasonographic (USG) with per-op findings. Histopathologic examination (HPE) report will be taken as confirmatory test. The need to study is to find out which is the most sensitive and specific investigation that can help us improve our diagnosis of acute appendicitis. Methods: The study was conducted in 100 consecutive patients of Acute Appendicitis at an Armed Forces Tertiary Care Hospital. Total leucocyte count (TLC), C-reactive protien (CRP), Lactate dehydrogenase (LDH) and Ultrasonographic (USG) findings were noted preoperatively. Per-operative findings were noted in all the patients. Histopathologic examination (HPE) of appendicectomy specimen was done in all cases. All investigations and USG findings were compared with per-operative findings and with HPE findings. Results: CRP has highest sensitivity and specificity (90%, 80%) followed by, USG (87.5%. 90%), WBC count (78.75%, 80%) and LDH (77.5%, 80%). When all the four tests are combined the sensitivity, specificity, positive predictive value and predictive value of negative test increased significantly (100%. 80%, 95.23%, 100% respectively). When all the four tests were negative, appendicitis could be safely ruled out and surgery could be avoided. Conclusion: With all the four tests were negative, appendicitis was ruled out and surgery was avoided thereby decreasing the rate of negative appendicectomy to 09%. TLC, CRP, LDH, USG should be used as aids in diagnosis of appendicitis. However no investigation can undermine the importance of clinical judgment. Good history and examination still remains the most valued tools in cases of acute appendicitis.