The most reliable way to determine if someone does not have appendicitis is to have them undergo a physical examination and diagnostic imaging. During the physical examination, the doctor will feel the abdomen for any tenderness, swelling, or pain that may indicate appendicitis. They will also ask the patient about any other symptoms that may be related to appendicitis, such as nausea, vomiting, and fever. If the doctor suspects that the patient may have appendicitis, they may order diagnostic imaging such as an abdominal ultrasound or CT scan. These tests can help determine the exact location and size of the appendix, and can also reveal any other potential causes of the patient’s symptoms. If the imaging results show that the appendix is normal in size and shape, then the patient does not have appendicitis. Additionally, in some cases, a doctor may also order a blood test to check for any signs of infection, as appendicitis is usually caused by a bacterial infection. If the blood test results are also normal, then it is likely that the patient does not have appendicitis.