Rationale: A common complaint in emergency medicine is acute abdominal pain. Because the underlying condition can be life threatening, rapid work-up is needed to establish an accurate diagnosis, including adequate choice of imaging techniques. History taking and physical examination are highly examiner-dependent, thus leading to the question: who is best to examine the patient with acute abdominal pain? In current practice almost all patients are examined by surgical residents or emergency department (ED) physicians. To our knowledge, no papers studied the inter-examiner differences between surgeons and residents/ED physicians in assessment of the (preliminary) diagnosis. Decisional tools can enhance diagnostic accuracy. We developed evidence based decisional tools for appendicitis and diverticulitis, since these are the most common diagnoses in acute abdominal pain. Before the widespread use of these decisional tools, their influence on accuracy and certainty of diagnosis must be evaluated. Repeated laboratory tests are useful in diagnosing appendicitis. However, the influence of repeated testing of WBC, CRP and procalcitonin on the accuracy of diagnosis in acute abdominal pain is not clear. The predictive value of procalcitonin in different common encountered diagnoses in acute abdominal pain is also unclear.
Objectives:  The main objective of this study is to evaluate the differences in accuracy of diagnosis between surgeons and surgical residents/ED physicians in patients with acute abdominal pain. In addition the influence of decisional tools for appendicitis and diverticulitis on the accuracy of diagnosis will be assessed. Secondary objectives include the evaluation of the influence of repeated laboratory measurements on the accuracy of diagnosis and the predictive value of procalcitonin for common diagnoses in acute abdominal pain.
Study design: This study is designed as a prospective cohort study, including consecutive adult patients, with non-traumatic acute abdominal pain (>2 hrs and < 5 days). Pregnant patients and patients in hemorrhagic shock are excluded.
Study parameters: The primary outcome is the accuracy of diagnosis of surgeons, surgical residents and ED physicians as well as the accuracy of diagnosis before and after the use of decisional tools for suspected appendicitis and diverticulitis.