Appendectomy is the most effective treatment option for acute appendisitis, which is the most commen emergent surgical pathology. However with in time period, surgical treatment borders are narrowed. Especially in uncomplicated acute appendicitis cases, nonoperative management (NOM) with antibiotherapies becomes primary treatment option. The COVID-19 pandemic, which is caused by 2019 novel coronavirus (2019-nCoV) and we encountered in the current process, has led to the re-questioning of surgical elective and emergency cases. Serious complications and increased mortality rates of the 2019-nCoV creates a novel problems of patient selection for emergent surgery and health care workers faced with potential health problems. As the same as the other surgical procedures, in the uncomplicated acute appendisitis cases NOM become more mandantory. NOM of uncomplicated acute appendisitis doen't increase perforation risk and general practice for decreasing surgical complications in the COVID-19 pandemic period. Additionally complicated acute appendicitis accounts for 20 to 30% of the patients undergoing appendectomy and lead to increased risk of postoperative complications, delayed recovery and longer hospital stay. Therefore, early diagnosis of complicated acute appendicitis is important; however, the most appropriate and inexpensive diagnostic method to make this diagnosis has not been established yet. Although the use of imaging methods is widespread, these methods are not accessible in many rural hospitals due to the high costs and unavailability of specialists. Thus, the need for an inexpensive and effective diagnostic technique allowing to make a differential diagnosis has not been met yet. For this purpose, several inexpensive and easily accessible blood parameter tests have been proposed; including the white blood cell count, immature granulocyte (IG) percentage, C-reactive protein levels or the neutrophil-to-lymphocyte ratio.

An increase in the IG count shows that the bone marrow is active. This parameter has been used as a prognostic factor in many infectious and non infectious diseases including sepsis, acute pancreatitis, and acute myocardial infarction. The Immature granulocyte (IG) fraction includes promyelocytes, myelocytes, and metamyelocytes but not band neutrophils or myeloblasts. The IG count and percentage has become an easy-to-use method, especially with the introduction of technological advances, as it can be easily determined using the results of a routine complete blood count.

It is aimed to efficacy of IG count and percentage which are calculated automatically in CBC samples, to differatiate the complicated and uncomplicated acute appendicitis cases with a cheap, easily applicable and cost effective test, especially in rural areas without enough diagnostic tests in COVID-19 pandemy.

The data of 146 patients elder than 18 years, who admitted to the Emergency Department and General Surgery outpatient clinic with the complaint of abdominal pain diagnosed with acute appendicitis and who were operated by the same surgical team between June 2018 and June 2019 were evaluated retrospectively after the approval of the local ethics committee. Patients' data were obtained by reviewing the patient follow charts, laboratory findings in the the electronic database of the hospital and epicrisis forms. Totally 76 patients excluded from the study; 22 patients were excluded because of the pathological diagnosis did not confirm acute appendicitis (negative appendectomies and appendiceal mucinous cystadenomas), 54 patients who were operated by the other surgical team were excluded.

The patients were assigned to the complicated acute appendicitis group (Group C) based on the preoperative imaging findings (periappendiceal abscess formation or significant periappendiceal fat tissue contamination in ultrasonography and computed tomography), intraoperative exploration findings (presence of gangrenous appendicitis, perforation or abscess formation), and pathological examination findings (acute phlegmonous appendicitis, acute gangrenous appendicitis or acute perforated appendicitis). The patients were assigned to the uncomplicated acute appendicitis group (Group UC) based on the increased diameter and wall thickness of the appendix and detection of minimal contamination in the surrounding fat tissue in the imaging tests; the presence of edema and the absence of gangrene, perforation or abscess in the the exploratory surgery of appendix, and confirmation of the diagnosis of acute appendicitis by the pathological examination findings [17-20].

The WBC, IG count and IG percentage automatically calculated in the complete blood count (CBC) parameters. WBC count, neutrophil count, lymphocyte count, and IG% were measured using an automated hematological analyzer (XN 3000; Sysmex Corp., Kobe, Japan) from blood samples obtained at the initial admission to the emergency department . Neutrophyl and Lymphocyte counts were obtained from automatically from the CBC parameters and NLR was calculated manually.

The demographic data (age, sex) of the patients, the white blood cell count (WBC), the neutrophil-to-lymphocyte ratio (NLR), and the IG count and percentage were evaluated retrospectively.

Statistical Analysis Statistical analyses were performed with the IBM Statistical Package for Social Sciences (SPSS) version 20.0 software. The student t-test or Mann-Whitney U test were used for analyzing the quantitive values based on normality of the distrubution calculated with Shapiro Wilk Test. The chi-square test or Fischer's exact test was used for analyzing the categorical data. ROC analysis was used to determeine spesivity and sensitivity of the parameters. Binary logistic regression analysis was performed to determine the preoperative diagnostic accuracy of the parameters. The quantitive data were given mean ± standard deviation (minimum - maximum values) or median (minimum - maximum values). The qualitative values were given number of cases (n) and percentage (%). A p-value of <0.05 was considered statistically significant.

Inclusion Criteria:

• Age >18 years,
• Patients diagnosed as acute appenditicitis cases according to clinical (preoperative and peroperative) and preoperative laboratory findings and imaging modalities (ultrasound, computed tomography), and pathologic results
• Patients who were operated by the same surgical team of the Kahramanmaras Sutcu Imam University Hospital.

Exclusion Criteria:

• Patients younger than 18 years,
• Negative appendectomies according to peroperative findings and pathologic findins
• Patients whose data were not available
• Patients who were operated by the other surgical team of the Kahramanmaras Sutcu Imam University.