title: A fertile-aged woman with right lower abdominal pain but unelevated leukocyte count and C-reactive protein. Acute appendicitis is very unlikely.
abstract: OBJECTIVE
  An uninflamed appendix at appendectomy represents a misdiagnosis. In fertile-aged women, the diagnostic accuracy in acute appendicitis is usually lower than 60%. We studied the role of preoperative leukocyte count and C-reactive protein (CRP) measurements in the diagnosis of acute appendicitis in fertile-aged women with a clinical suspicion of acute appendicitis. In particular, what is the clinical value of unelevated leukocyte count and CRP in excluding acute appendicitis in these patients?
  
  
  METHODS
  We calculated the mean leukocyte count and CRP values in (1) 100 consecutive fertile-aged women operated on for a clinical suspicion of acute appendicitis but with an uninflamed appendix found at appendectomy, and (2) 100 consecutive fertile-aged women operated on for a clinical suspicion of acute appendicitis and acute appendicitis found at appendectomy. The percentages of patients with (1) both values unelevated, (2) only leukocyte count elevated, (3) only CRP value elevated, or (4) both values elevated were calculated within the groups A (uninflamed appendix) and B (acute appendicitis).
  
  
  RESULTS
  The mean leukocyte value was significantly (P<0.001) higher in patients with acute appendicitis (13.7x10(9)/l) than in those with an uninflamed appendix (10.6x10(9)/l). Similarly, the mean CRP value was significantly (P<0.05) higher in patients with acute appendicitis (42 mg/l) than in those with an uninflamed appendix(29 mg/l). Taken together, 24 patients were operated on for a clinical suspicion of acute appendicitis, although preoperative leukocyte count and CRP values were unelevated. An uninflamed appendix was found in all these patients at appendectomy.
  
  
  CONCLUSIONS
  Although clinical symptoms and signs indicated acute appendicitis, unelevated leukocyte count and CRP values excluded it, with a 100% predictive value in the current study of fertile-aged women. In our patients, 24% (24 of 100) of unnecessary appendectomies could have been avoided by trusting in this finding.
authors.affiliation: Department of Surgery, University of Turku, PB 52, FIN-20521 Turku, Finland.
authors.forename: J M
authors.initials: JM
authors.lastname: Grönroos
authors.forename: P
authors.initials: P
authors.lastname: Grönroos
mesh_terms: D015746:Abdominal Pain / Q000097:blood / Q000209:etiology*; D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001064:Appendicitis / Q000097:blood / Q000175:diagnosis* / Q000601:surgery; D002097:C-Reactive Protein / Q000032:analysis*; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007958:Leukocyte Count; D011237:Predictive Value of Tests; D011300:Preoperative Care; D012189:Retrospective Studies; D012680:Sensitivity and Specificity
chemical_list: D002097:C-Reactive Protein