Objective: To evaluate the efficacy of biochemical tests in diagnosing acute appendicitis.
Design: Open prospective study.
Setting: District hospital, Norway.
Subjects: 257 patients with suspected acute appendicitis.
Interventions: Initial diagnostic accuracy of a logistic regression model using available clinical data was compared with results of corresponding models that included an increasing number of inflammatory parameters.
Main outcome measures: The estimated probabilities of appendicitis in different testing groups were analysed using receiver operating characteristic (ROC) curves.
Results: A model including only clinical variables had a mean area under the ROC curve of 0.854. When the total white blood cell count, C-reactive protein concentration, and neutrophil count were added, the model improved significantly to 0.920.
Conclusion: Biochemical tests are of additional value in a computer model, and the tests should, if used rationally, also provide physicians with important information in the investigation of acute appendicitis.