Does a Negative Triple Test Reduce the Rate of Negative Appendectomy in Adults?

Abstract

Mahmoud F. Sakr, Hossam M. Hamed, Hisham M. Al-Torky

Objectives: To investigate the negative predictive value (NPV) of the triple test (total leukocyte count [TLC], neutrophil percentage [NP], and C-reactive protein [CRP] level) in the diagnostic accuracy of acute appendicitis by reducing negative appendectomy rates (NARs) in adult patients. Methods: The present prospective clinical study included 348 consecutive patients admitted to Ahmadi Hospital, Kuwait during 2010 and 2011 with the possible diagnosis of acute appendicitis. Children (<16 years) (n=61) and pregnant women (n=5) were excluded. The remaining 282 patients were enrolled but only those with an NTT (n=102) were analyzed (study population). The NTT meant TLC <11,000/µL, NP <75%, and CRP <5 mg/L. The data collected included demographics, clinical presentation, laboratory tests, histopathology, and outcome, and the NPV was calculated. Results: Sixty-seven patients (65.9%) were female and 35 (34.1%) were male. Their ages ranged between 16 and 49 years (mean 27.5 years). Most patients (87.3%) had their symptoms for 12-36 hours before hospital admission. The mean values for TLC, NP, and CRP were 7,573/µL, 54.53%, and 0.61 mg/L, respectively. Of the 102 patients with NTT, 101 (99%) proved not to have appendiceal inflammation (NPV=99%). Only 39 patients were operated upon, of whom 38 (97.4%) had a normal appendix, and the remaining 63 patients were either discharged (n=47) or referred to other specialties (n=16). There were significantly more women (76.3%, 29/38) with negative appendectomy than men (24.7%, 9/38) (X2= 21.1, p=0.0001). Gynecological causes were the most common (60.5%, 23/38) and in 11 cases, the exact etiology could not be identified. Conclusions: From the data presented, it may be concluded that TLC, NP and CRP blood levels (triple test) should be measured upon hospital admission of adult patients with clinically suspected acute appendicitis. If used judiciously, they may spare the group of patients with an NTT an unnecessary surgical operation, hence markedly reducing the NAR with its potential risks.