Original Contribution Alvarado score: can it reduce unnecessary computed tomographic scans for evaluation of acute appendicitis? ☆ Piyaporn Apisarnthanarak, MD a , Voraparee Suvannarerg, MD a , Poompis Pattaranutaporn, MD a , Aphinya Charoensak, MD a , Steven S. Raman, MD b , Anucha Apisarnthanarak, MD c, ⁎ a Department of Radiology, Faculty of Medicine Siriraj Hospital, Bangkok, Thailand b Department of Radiology, David Geffen School of Medicine at UCLA, Los Angeles, CA, USA c Division of Infectious Diseases, Thammasart University Hospital, Pratumthani, Thailand abstract article info Article history: Received 6 May 2014 Received in revised form 29 November 2014 Accepted 29 November 2014 Available online xxxx Objective: The objective of the study is to assess the utility of Alvarado score in the diagnosis of acute appendicitis and the utility of computed tomographic (CT) scan for evaluation of acute appendicitis when stratified by Alvarado scores. Materials and methods: Retrospective cohort study comprised adult patients who underwent abdominal CT for suspected acute appendicitis between January 2006 and December 2009. Two abdominal radiologists indepen- dently reviewed the CT scans; any discrepancies were resolved by a consensus review. Alvarado scores were cal- culated and categorized as low (0-3), equivocal (4-6), or high (7-10) probability for appendicitis. The diagnostic utility of CT scans and Alvarado score for acute appendicitis were compared with the criterion standard of com- bined medical chart review and pathology findings. Results: In a cohort of 158 subjects, 73 (46.2%) had clinical diagnoses of acute appendicitis. The accuracy, sensitiv- ity, specificity, positive predictive value, and negative predictive value of CT scan in the diagnosis of acute appen- dicitis were 97.5%, 98.6%, 96.5%, 96.0%, and 98.8%, respectively. The mean Alvarado score for subjects with complicated appendicitis was significantly higher (7.95) than subjects with uncomplicated appendicitis (6.67) and those with other diagnoses (5.95). Acute appendicitis was confirmed in 2 (13.3%) of 15 subjects with low probability Alvarado scores, 16 (30.8%) of 52 subjects with equivocal scores, and 55 (60.4%) of 91 subjects with high probability scores. Conclusion: The CT scan had high diagnostic utility for acute appendicitis. The Alvarado score was not a reliable independent predictive tool for acute appendicitis and could not replace CT scan. © 2014 Elsevier Inc. All rights reserved. 1. Introduction Acute appendicitis is the most common reason for an acute surgical assessment of the abdomen, with an estimated 6% lifetime event risk in the general population [1,2]. The clinical diagnosis of acute appendicitis is principally based on symptoms, signs, and laboratory data. Together, these clinical and laboratory factors may be unreliable in up to 40% of premenopausal women [3]. The differential diagnosis includes colonic diverticulitis; epiploic appendagitis; and gynecologic emergencies such as pelvic inflammatory disease, ruptured ovarian cyst, ovarian tor- sion, and tubal pregnancy. This diagnostic problem has led to a high negative appendectomy rate (NAR) of 12% among women of reproduc- tive age compared to 2% in the general population, even with CT scan imaging [4,5]. Appendiceal perforation rates are higher in children (40%-57%) and the elderly (55%-70%), compared to the overall inci- dence of 16% to 39%, with additional diagnostic challenge attributed to the difficulty in obtaining a history and performing the physical exami- nation [6]. The utility of computed tomographic (CT) scan in acute appendicitis enables high accuracy in early diagnosis and reduction in morbidity at- tributed to perforation [6-9]. Unlike ultrasound, a true alternate diagno- sis for abdominal pain may be evident if the appendix appears normal [7,9]. Raman et al [7] showed that, in adult patients suspected of having appendicitis but confirmed later as not having acute appendicitis, CT scan suggested an alternative diagnosis in 65.4% of cases (266 in 407). Alternative diagnoses included colon-related causes (ie, colitis and di- verticulitis) in 34.6%, small bowel related causes (ie, small bowel ob- struction and inflammatory bowel diseases) in 27.4%, gynecologic causes (ie, ruptured ovarian cyst, ovarian mass, and tuboovarian ab- scess) in 10.2%, and other causes (ie, acute cholecystitis and acute pan- creatitis) in 27.8%. In general, CT scans perform uniformly high at diagnosing appendicitis with 99% sensitivity and 95% specificity [10], re- gardless of scanning techniques or combinations of oral, rectal, or intra- venous (IV) contrasts. There has been a consequent increase in the use American Journal of Emergency Medicine xxx (2014) xxx–xxx ☆ Disclosure: AA was supported by the National Research University Project of the Thailand Office of Higher Education Commission. ⁎ Corresponding author at: Division of Infectious Diseases, Thammasart University Hospital, Pratumthani 12120 Thailand. Tel.: +66 81 987 2030. E-mail address: anapisarn@yahoo.com (A. Apisarnthanarak). http://dx.doi.org/10.1016/j.ajem.2014.11.056 0735-6757/© 2014 Elsevier Inc. All rights reserved. Contents lists available at ScienceDirect American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem Please cite this article as: Apisarnthanarak P, et al, Alvarado score: can it reduce unnecessary computed tomographic scans for evaluation of acute appendicitis?, Am J Emerg Med (2014), http://dx.doi.org/10.1016/j.ajem.2014.11.056