Purpose: Appendectomy is one of the most common surgical procedures all over the world. Although various laboratory tests and imaging studies are available to improve the accuracy of diagnosis, the rate of negative appendectomy is still about 15-30%. This study was designed to assess the diagnostic value of quantitative C-reactive protein (CRP) in patients suspected to acute appendicitis.
Materials and methods: In a prospective study, blood samples of 102 patients were collected before appendectomy. CRP was measured by immunoturbidimetry and the data were compared with the final histopathologic reports. Diagnostic accuracy of the CRP test was analyzed by ROC curve.
Results: In histopathology, 83 patients (81/4%) had acute appendicitis and 19 (18/6%) had normal appendices. Considering 14 mg/lit as the cut-off point, this test shows 59% (95% CI, 48-69%) sensitivity and 68% (95% CI, 47-88%) specificity. The positive and negative predictive values were 89% (95% CI, 80-97%) and 27% (95% CI, 14-39%), respectively.
Conclusions: The measurement of CRP levels is not an ideal diagnostic tool for ruling out or determination of acute appendicitis.