An evaluation of the utility of additional tests in the preoperative diagnostics of acute appendicitis

Determining the optimum algorithm for diagnostic procedure in suspected acute appendicitis (AA) may not only reduce the number of unnecessary operations, but also the frequency of complications, and may contribute measurably to reducing the costs of treating patients with acute abdominal conditions.

The aim of the study was to assess the value of standard diagnostic methods and measurement of selected biochemical and hematological parameters (C-reactive protein, CRP; interleukin-6, IL-6; procalcitonin, PCT; total count of white blood cell, WBC) in the accuracy of preoperative AA diagnosis.

The prospective study included 132 patients (female: 52.3%, male: 47.7%) emergency admitted to the Surgical Department, aged 15 to 74 years (mean 36 years), with a suspicion of appendicitis. Measurement of PCT concentration was carried out by immunoluminometric assay, IL-6 concentration by micro enzyme-linked immunosorbent assay and CRP concentration by immunonephelometric assay. Statistical analysis was done by the chi-square test and Fisher's exact test for categorized discrete variables, and the Mann–Whitney U and Kruskal–Wallis tests for continuous variables. In order to assay the diagnostic utility of tests, the receiver operating characteristic model of curve analysis was used.

AA was confirmed in 89 (67.5%) of the patients operated on (group A). Twenty-six (19.7%) of the patients were not operated on and did not require surgery (group C); in 13 patients (9.8%) operated with a preliminary diagnosis of AA, no changes in the appendix were found during the course of the operation (group B). Four (3%) of the patients treated conservatively for periappendicular infiltration were excluded from the following analysis (group D). The mean count of WBC in AA was 13.22 ± 4.45 × 103/μL, with no statistical significance between groups, which does not allow the patients requiring surgery to be distinguished. The highest elevation of IL-6 concentration was observed in the group with the AA and the periappendicular infiltration: 101.5 ± 355.9 vs. 173.6 ± 228.33 pg/mL, respectively; p < 0.05. No surgery patients of group C showed considerably lower CRP concentrations than those of group D: CRP: 2.05 ± 3.6 vs. 6.36 ± 4.74 mg/L; p < 0.05. In cases of advanced forms of AA, the gangrenous with perforation, higher marker values are obtained than those in the phlegmonose form (186.60 ± 541.2 vs. 40.08 ± 48.3 pg/mL; (p < 0.05) for IL-6 and 8.88 ± 7.45 vs. 2.84 ± 3.83 mg/L; (p < 0.001) for CRP, respectively).

1. AA diagnosis based only on an assessment of clinical status may lead to an increase in the number of people operated with false-positive diagnoses of AA. 2. Applying additional diagnostic methods such as IL-6 determination seems to be useful in reducing the numbers of false-positive diagnoses of AA. 3. Laboratory tests, i.e., CRP, IL-6, and PCT are much more useful in assessing the risk of complications during the course of AA.