Re: Predictive value of white cell count and C-reactive protein in children with appendicitis.

Abstract

We have read with interest the article concerning the predictive value of white blood cell count and C-reactive protein in children with appendicitis by Betràn et al [ [1] Betràn M.A. Almonacid J. Vicencio A. Guitièrrez J. Cruces K.S. Cumsille M.A. Predictive value of white cell count and C-reactive protein in children with appendicitis. J Pediatr Surg. 2007; 42: 1208-1214 Abstract Full Text Full Text PDF PubMed Scopus (102) Google Scholar ] that was recently published in your journal. Although the article was of interest, we have some comments about how the study was performed and the conclusions drawn from it. The authors undertook the task of defining a possible relationship between raised inflammatory markers and acute appendicitis, hoping to be able to use it as an aid in diagnosing the condition. The cohort group consisted of patients who underwent appendicectomy, with histology providing the gold standard of diagnosis. No mention is made of patients who were admitted with the presumptive diagnosis of appendicitis and were not operated on for whatever reason, more specifically what their inflammatory markers were. Conditions such as urinary tract infections, gastroenteritis, and acute mesenteric lymphadenitis may cause these biochemical values to be elevated in the absence of appendicitis. Had these factors been considered, a sensitivity of 1.0 at 0 to 12 hours for white cell count would probably not have been achieved. Other important information not mentioned was the proportion of patients who were treated with antibiotics before admission and before surgery and how this affected their blood results, as well as time from admission to surgery, more factors that could affect inflammatory marker levels. Their conclusion that inflammatory markers can support the clinical diagnosis of appendicitis has been proven in history [ [2] Stefanuti G. Ghirardo V. Gamba P. Inflammatory markers for acute appendicitis in children: are they helpful?. J Pediatr Surg. 2007; 42: 773-776 Abstract Full Text Full Text PDF PubMed Scopus (55) Google Scholar ]. However, it cannot be used to empirically differentiate patients with or without appendicitis because several other factors need to be assessed to rule out common differentials such as urinary tract infection, gastroenteritis, mesenteric lymphadenitis, and others. This is a well-presented article. We wonder whether its value could not be increased by calculating the negative predictive value of inflammatory markers in patients presenting with acute right iliac fossa pain suspicious of acute appendicitis and who are consequently discharged with another diagnosis.