A fertile-aged woman with right lower abdominal pain but unelevated leukocyte count and C-reactive protein - Acute appendicitis is very unlikely

Background and aims: An uninflamed appendix at appendectomy represents a mi sdiagnosis. In fertile-aged women, the diagnostic accuracy in acute appendi citis is usually lower than 60%. We studied the role of preoperative leukoc yte count and C-reactive protein (CRP) measurements in the diagnosis of acu te appendicitis in fertile-aged women with a clinical suspicion of acute ap pendicitis. In particular, what is the clinical value of unelevated leukocy te count and CRP in excluding acute appendicitis in these patients? Methods : We calculated the mean leukocyte count and CRP values in (1) 100 consecut ive fertile-aged women operated on for a clinical suspicion of acute append icitis but with an uninflamed appendix found at appendectomy, and (2) 100 c onsecutive 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 elev ated, (3) only CRP value elevated, or (4) both values elevated were calcula ted within the groups A (uninflamed appendix) and B (acute appendicitis). R esults: The mean leukocyte value was significantly (P<0.001) higher in pati ents with acute appendicitis (13.7x10(9)/l) than in those with an uninflame d 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 op erated on for a clinical suspicion of acute appendicitis, although preopera tive leukocyte count and CRP values were unelevated. An uninflamed appendix was found in all these patients at appendectomy. Conclusion: Although clin ical symptoms and signs indicated acute appendicitis, unelevated leukocyte count and CRP values excluded it, with a 100% predictive value in the curre nt study of fertile-aged women. In our patients, 24% (24 of 100) of unneces sary appendectomies could have been avoided by trusting in this finding.