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Acute appendicitis in adults: Diagnostic evaluation

Ronald F Martin, MD
Section Editor
Martin Weiser, MD
Deputy Editor
Wenliang Chen, MD, PhD


The diagnosis of acute appendicitis is typically based upon the findings from the medical history and clinical examination and is supported by the laboratory and/or imaging findings.

This topic will review the diagnostic studies, including radiographic studies and laboratory tests that can assist in establishing the diagnosis of acute appendicitis in the adult. The clinical manifestations of acute appendicitis and the operative and nonoperative management are reviewed as separate topics. (See "Acute appendicitis in adults: Clinical manifestations and differential diagnosis" and "Management of acute appendicitis in adults".)


The diagnosis of acute appendicitis is generally made from the history and clinical examination; the diagnosis is supported by the laboratory and/or imaging findings. The patient presenting with acute abdominal pain should undergo a thorough physical examination, including a digital rectal examination. Women should undergo a pelvic examination. (See "Causes of abdominal pain in adults" and "Evaluation of the adult with abdominal pain".)

An experienced examiner can make the correct diagnosis of appendicitis without imaging [1]. Several studies have found the diagnostic accuracy of clinical evaluation alone to be 75 to 90 percent [2-5]. The diagnostic accuracy of the clinical examination may depend on the experience of the examining clinician [6-11]. Patients in whom appendicitis is considered to be extremely likely after assessment by an experienced clinician should proceed directly to appendectomy without further radiologic testing. (See "Management of acute appendicitis in adults".)

The diagnosis of acute appendicitis can be difficult and a delay can result in perforation rates as high as 80 percent [12,13]. However, a retrospective review of 9048 adults with acute appendicitis found that the mean time from presentation to operation (8.6 hours) was not associated with risk of perforation [14]. Factors associated with increased risk of perforation included male gender (RR 1.24, 95% CI 1.08-1.43), increasing age (RR 1.04, 95% CI 1.08-1.43), three or more comorbid illnesses (RR 2.8, 95% CI 1.36-3.49), and lack of medical insurance coverage (RR 1.43, 95% CI 1.24-1.66).


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Literature review current through: Sep 2016. | This topic last updated: May 25, 2016.
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