How effective are WBC count and C-reactive protein (CRP) in ruling out the diagnosis of appendicitis?

Updated: Jul 23, 2018
  • Author: Sandy Craig, MD; Chief Editor: Barry E Brenner, MD, PhD, FACEP  more...
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Investigators have also studied the ability of combinations of white blood cell (WBC) count and CRP to reliably rule out the diagnosis of appendicitis. Gronroos and Gronroos found that the WBC count or CRP level was abnormal in all 200 patients with appendicitis in their cohort of 300 patients operated for suspected appendicitis. [28] Ortega-Deballon et al found that a normal WBC count and CRP level had a negative predictive value of 92.3% for the presence of appendicitis in prospectively studied patients referred to a surgeon for RLQ pain. [29]

Some studies have examined the sensitivity of a combined WBC count and CRP level in the subpopulation of patients older than 60 years. Gronroos studied 83 patients older than 60 years who underwent appendectomy (73 found to have appendicitis) and found that no patient with appendicitis had both a normal WBC count and CRP level. [30] Yang et al retrospectively studied 77 patients older than 60 years with histologically proven appendicitis and found that only 2 had a normal "triple screen." [31]

Several studies also examined the accuracy of the WBC count and CRP level in the subpopulation of pediatric patients with suspected appendicitis. Gronroos evaluated 100 children with pathology-proven appendicitis and found that both the WBC count and CRP level were normal in 7 of 100 patients. [32] Stefanutti et al prospectively studied more than 100 children undergoing surgery for suspected appendicitis and found that either the WBC count or CRP level was elevated in 98% of those with pathology-proven appendicitis. [33]


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