History and Objectives: The inaccuracy of available diagnostic methods leads to an unacceptable high negative appendectomy and perforation rate. Our objective was to determine the value of clinical symptoms/signs and WBC differential count in the diagnosis of appendicitis in order to improve the accuracy of clinical diagnosis.
Materials and Methods: In a clinical trial study, 914 consecutive patients with a clinical diagnosis of appendicitis, the value of abdominal pain and tenderness, pain shift, anorexia, vomiting, fever, tachycardia, leukocytosis and neutrophilly determined on the basis of PPV and NPV then analyzed by Chi-square test.
Results: From total of 914 patients evaluated, 61% were males and 39% females. The mean age was 24.7±12.4 years. Pathology revealed 700 positive appendicitis (Cases) and 214 negative appendectomy (Control). The most accurate diagnostic factors were neutrophilly leukocytosis and pain shift. Neutrophilly had a PPV=85 which means 15% diagnostic failure. In had NPV=38 which means 62% of patients who have not neutrophilly will have positive appendicitis (P<0.0005), so this factor has a poor diagnostic value. Obviously other clinical and laboratory factors will have lower accuracy than neutrophilly, thus none will have any diagnostic value by themselves alone. For this reason, diagnostic values of more common symptoms were examined in combination for diagnosis of appendicitis. The most common and accurate factors were the combination of pain shift, anorexia, vomiting, leukocytosis and neutrophilly with PPV=92.4 and NPV=36, which means only a 7.6% diagnostic failure.
Conclusion: None of the clinical criteria and leukocytosis alone could have diagnostic power to predict appendicitis, however, the combination of several factors have more accurate predictive value and reduce the false appendectomy rate. The study revealed that with more attention to clinical symptoms, signs, leukocytosis and neutrophilly can improve clinical diagnosis and result in lower negative appendectomy and perforation rate significantly (P<0.0005).