BACKGROUND Cytokines and leukocyte adhesion molecules are activated and found in increased concentrations in bacterial infection. The purpose of this study was to investigate whether some of these new serum markers could be feasible as a single on-admission test to predict acute appendicitis (AA). METHODS In an open prospective study the diagnostic potentials of two cytokine measurements (interleukin-6 and interleukin-8), soluble leukocyte adhesion molecule (CD44), C-reactive protein (CRP) and white blood cell (WBC) count were compared in 80 consecutive patients who had undergone surgery for suspected AA. The diagnostic performance of each parameter was tested by using receiver operating characteristic (ROC) curves. RESULTS Phlegmonous AA was found in 34%, gangrenous AA in 40% and perforated AA in 5% of the patients. The proportion of negative explorations was 21%. Preoperative serum concentrations of IL-6 and CRP were elevated only in gangrenous and perforated AA. The concentrations of IL-8 and CD44 remained unchanged in AA. The sensitivity (84%), specificity (79%) and diagnostic accuracy (82%) of IL-6 were higher than the values for CRP, WBC, IL-8 and CD44 in predicting AA. CONCLUSIONS ROC analysis confirmed that IL-6 showed the best trend in the diagnosis of AA. However, the diagnosis of AA was not greatly improved by any of the new serum markers as single on-admission tests.