Predictive value of C-reactive protein with Alvarado score in acute appendicitis

The aim of the study was to evaluate whether C-reactive protein (CRP) level on admission could aid the diagnostic accuracy of Alvarado score in acute appendicitis.

We retrospectively evaluated hospital records and database of 234 patients (men 116, women 118, median age 28 years, range 15-87 years) who underwent appendicectomy for acute appendicitis. Patients were categorized into three groups retrospectively based on the Alvarado score. Group I: score 7-10 (n = 155), group II: score 4-6 (n = 71), group III: score less than 3 (n = 10). Negative (NPV) and positive predictive values (PPV) of CRP was calculated.

Overall, 169 of 234 (72.2%) had histopathological confirmation of acute appendicitis. The predicted accuracy of Alvarado score was 84.5% in group I, 50.7% in group II and 25% in group III. The PPV of high CRP and NPV of normal CRP for group I was 88% and 36.4%, in group II, 63% and 72%, in group III, 33% and 86%, respectively.

The Alvarado score and CRP taken together improve the predictive value of diagnosing acute appendicitis. Having a normal CRP in the equivocal group of Alvarado 4-6, should be further evaluated by advanced imaging before proceeding to appendicectomy.