The Adult Appendicitis Score (AAS) calculator assesses the likelihood of acute appendicitis by evaluating patient symptoms and lab results. Users input data related to seven key indicators which are translated into numerical scores based on established categories. The scoring system assigns weights to patient symptoms and lab values as follows:

- Right Lower Quadrant Pain:
  - Yes = 2 points
  - No = 0 points

- Pain Relocation:
  - Yes = 2 points
  - No = 0 points

- Right Lower Quadrant Tenderness:
  - Present, male = 3 points
  - Present, female aged 16-49 years = 1 point
  - Present, female aged > 50 years = 3 points
  - Absent = 0 points

- Guarding:
  - None = 0 points
  - Mild = 2 points
  - Moderate or severe = 4 points

- White Blood Cell Count (×10⁹/L):
  - ≥ 7.2 and < 10.9 = 1 point
  - ≥ 10.9 and < 14.0 = 2 points
  - ≥ 14.0 = 3 points

- Neutrophils (%):
  - ≥ 62 and < 75 = 2 points
  - ≥ 75 and < 83 = 3 points
  - ≥ 83 = 4 points

- C-Reactive Protein, mg/L (for symptoms > 24 hours):
  - ≥ 4 and < 11 = 2 points
  - ≥ 11 and < 25 = 3 points
  - ≥ 25 and < 83 = 5 points
  - ≥ 83 = 1 point
  (alternative ranges for CRP are scored similarly based on different thresholds)

To compute the AAS score, each input response is translated into its respective point value. These scores are summed to produce a total score ranging between 4 and 23. This total score then helps provide a snapshot of appendicitis risk:

- A score of 10 or lower suggests a low risk of acute appendicitis.
- Scores from 11 to 15 indicate an intermediate risk.
- A score of 16 or higher points to a high risk of acute appendicitis.

These interpretations guide clinicians in assessing the probability of appendicitis, allowing for more informed decision-making in potential cases.

The Adult Appendicitis Score (AAS) is a clinical calculator used in the evaluation of adult patients who present with suspected acute appendicitis. This scoring system is designed to aid in the diagnosis of appendicitis, helping to stratify patients into low, intermediate, and high-risk categories based on a variety of clinical factors such as symptoms, physical examination findings, and laboratory results. The AAS can help guide clinical decision-making, potentially reducing the need for unnecessary imaging or surgery in low-risk patients. It is not applicable to pediatric patients, pregnant women, or individuals with previous appendectomy. It should also not be used in patients with other clear causes of abdominal pain.