Rapid C-reactive protein (CRP) measurements in the diagnosis of acute appendicitis.

C-reactive protein (CRP) has been measured in plasma of patients with acute appendicitis and in controls without appendicitis to test the accuracy and diagnostic performance of a new rapid test kit for CRP (NycoCard CRP). The values obtained for CRP by the rapid test correlated well (Rs = 0.92) with the reference method for measuring CRP. The sensitivity, specificity and predictive values were calculated at different cut-off values. At values > 10 mg l-1 a sensitivity of 58% and a negative predictive value of 72% were found. Higher values of sensitivity were observed for men than for women, 69% and 44% respectively. Patients with acute appendicitis who had had symptoms for more than 24 h, had elevated CRP values (cut-off > 10 mg l-1) in more than 80% of cases. Our study shows that the rapid CRP test and the reference CRP test gave an almost identical result.