Acute abdomen is a frequently encountered clinical condition that can be fatal if not diagnosed early. Acute appendicitis is one of the causes of acute abdomen and is the most common clinical condition leading to acute abdomen worldwide. Therefore, early diagnosis is crucial. Delays in diagnosis can lead to the complication of appendicitis and an increase in its complications, further worsening the clinical picture and raising morbidity and mortality rates.

In patients diagnosed with acute appendicitis, distinguishing between complicated and uncomplicated appendicitis is vital for treatment planning. The evaluation of patients' laboratory and radiological findings are widely used methods in clinical practice for this differentiation.

Recent studies have shown the HALP score has become a new prognostic biomarker in the literature, used to predict a range of clinical outcomes in various neoplasms. To date, the HALP score has been used to evaluate outcomes and prognosis in gastric, colorectal, bladder, prostate, and other cancers, as well as in many other diseases.

The purpose of this study is to determine the clinical impact of using the preoperatively calculated HALP score, derived from blood parameters, in the diagnosis, detection, and treatment of complicated acute appendicitis cases in the preoperative period without the need for additional diagnostic methods.

*Aim of the Study Acute abdomen is a frequently encountered clinical condition that can be fatal if not diagnosed early. Numerous diseases can cause acute abdomen, making accurate and rapid diagnosis extremely important. Acute appendicitis is one of the causes of acute abdomen and is the most common clinical condition leading to acute abdomen worldwide.

In a study by Addiss et al., the incidence of acute appendicitis was approximately 233 per 100,000 people. Although slightly more common in males, there is a lifetime risk of about 7%.

Therefore, early diagnosis is crucial. Delays in diagnosis can lead to the complication of appendicitis and an increase in its complications, further worsening the clinical picture and raising morbidity and mortality rates.

The reported incidence of complicated appendicitis and its complications in various studies ranges from approximately 20% to 30%. This significant rate increases the risk of morbidity and mortality. Thus, early diagnosis and treatment of appendicitis are of great importance to prevent the development of complications.

In patients diagnosed with acute appendicitis, distinguishing between complicated and uncomplicated appendicitis is vital for treatment planning. The evaluation of patients' laboratory and radiological findings are widely used methods in clinical practice for this differentiation.

Alongside laboratory and radiological findings, commonly used scoring systems are also available. Among these, the Alvarado scoring system, first described in 1986, is the most frequently used and popular system, and it remains the primary system consulted in patients with a preliminary diagnosis of acute appendicitis.

Beyond the Alvarado score, the Appendicitis Inflammatory Response (AIR) score, a more recently developed system, is also gaining widespread use. Furthermore, scoring systems created using artificial intelligence with current technologies have also been described.

In recent years, a new scoring system, the HALP score, was first developed by Chen et al. to predict the prognosis of gastric carcinomas. This score is calculated as [hemoglobin (g/L) × albumin (g/L) × lymphocytes (/L)] / platelets (/L).

Recent studies have shown the HALP score has become a new prognostic biomarker in the literature, used to predict a range of clinical outcomes in various neoplasms. Its use has become widespread because HALP is a scoring system composed of routinely used parameters, such as platelet and lymphocyte counts, albumin (indicating nutritional status), and hemoglobin (indicating anemic status).

To date, the HALP score has been used to evaluate outcomes and prognosis in gastric, colorectal, bladder, prostate, and other cancers, as well as in many other diseases.

The purpose of this study is to determine the clinical impact of using the preoperatively calculated HALP score, derived from blood parameters, in the diagnosis, detection, and treatment of complicated acute appendicitis cases in the preoperative period without the need for additional diagnostic methods.

• Material-Methods This study was planned as a retrospective study. For this purpose, it was planned to include patients who were diagnosed with acute appendicitis and operated on in Elazığ Fethi Sekin City Hospital General Surgery Clinic between 01.01.2020 and 01.01.2025. Complete blood count (CBC) and biochemistry values of the patients studied in the preoperative period were recorded by retrospective file scanning. Patients will be divided into two groups according to the postoperative pathology results and exploration findings by examining the pathology results and surgery notes recorded in the system, as complicated acute appendicitis (pathological diagnosis of gangrenous, phlegmonous, perforated or presence of perforation, abscess or plastron in surgical exploration) and uncomplicated acute appendicitis (pathological diagnosis of acute appendicitis). Preopartive HALP score levels will be compared between groups. Since the study is planned retrospectively, the sample size will not be calculated.
• Data Collection Tools Patients' age, gender, complete blood count (CBC), biochemistry, and pathology data will be evaluated.
• Statistical Analysis Data analysis will be performed using the IBM Statistical Analysis for Social Sciences (SPSS) ver 20 statistical software package. The Shapiro-Wilk test will be conducted to assess the normality of distribution for numerical data. Based on the normality of distribution, either the Student's t-test or the Mann-Whitney U test will be used. Numerical data will be presented as mean ± standard deviation (minimum - maximum values) or median (95% Confidence Interval), depending on their conformity to normal distribution.

For comparing categorical data, the Chi-square analysis or Fisher's exact test will be used. Categorical data will be presented as count (n) and percentage (%). Univariate analysis will be performed to identify factors effective in the preoperative prediction of complicated acute appendicitis, followed by multivariate analysis. A probability value of P<0.05 will be considered statistically significant.

Inclusion Criteria:

• Being over 18 years of age
• Having undergone surgical treatment for a diagnosis of acute appendicitis (Laparoscopic or conventional open surgery)
• Patients with no missing data in their records

Exclusion Criteria:

• Patients under 18 years of age
• Cases of uncomplicated acute appendicitis diagnosed but treated medically
• Patients with incomplete data
• Those with chronic kidney and liver failure
• Patients with liver diseases such as Wilson's disease or alpha-1 antitrypsin deficiency
• Individuals with hematological malignancies like ALL or AML
• Patients with genetic bleeding disorders such as hemophilia

Patients operated diagnosed as acute appendicitis.