Objective: It is generally a gruelling job to diagnose the appendicitis, the most common cause of a surgical operation in childhood. In this study, we aimed to reveal the relationship between the values obtained by the preoperative Complete Blood Count, and the Neutrophile Lymphocyte - Platelets Lymphocyte Ratio which are derived from the Complete Blood Count, and pathologically diagnosed appendicitis subgroups which are uncomplicated acute appendicitis (AA), suppurative appendicitis (SA) and gangrenous appendicitis (GA).

Materials and Methods: The Complete Blood Counts and the ratio derived from the Complete Blood Count of a total of 392 cases, under 18 years old, are studied in this work. All these cases had been the patients of our hospital between 2013 and 2015. 291 of them were diagnosed for appendicitis while 101 were healthy.

Results: For patients and control groups with similar ages and same gender, an on-the-edge statistically significant increase for the Mean Platelet Volume is observed (p=0,042). For the Leucocyte, Neutrophile, Lymphocyte count, Neutrophile percentage, Neutrophile Lymphocyte Ratio and Platelets Lymphocyte Ratio ( p<0,001 for all) which exhibit advanced significant increase (decrease for Lymphocyte count), ROC analysis show that the AUC (Cut-off) values are 0,892 (>9,89); 0,813 (>6,57); 0,760 (≤2,40); 0,821 (>68); 0,857 (>2,35) and 0,706 (>111,62), respectively.

Conclusion: Early diagnosis of the cause of most common childhood medical operation, the appendicitis, is vital for patients. Along with various well-known tests and examinations, such as physical examinations, radiodiagnosis and low-predictive laboratory tests, it has been realized that the Neutrophile Lymphocyte - Platelets Lymphocyte Ratio can be used for early diagnosis of appendicitis as well.