[The value of C-reactive protein in the diagnosis of acute appendicitis in children].

OBJECTIVE

The aim of this study was to evaluate the usefulness of C-reactive protein values in the diagnosis of acute appendicitis, either as a single test or in combination with total white cell count.

PATIENTS AND METHODS

Two hundred and thirty-one children with suspected appendicitis were analyzed. C-reactive protein and total white cell counts were measured and compared with the duration of symptoms and histological diagnosis. Both tests were compared by receiver-operating characteristic curves and the probability for the use of both tests together was calculated.

RESULTS

Ninety out of 231 patients had abdominal pain that did not demand surgery. One hundred and forty-one children had histologically confirmed appendicitis (subgroups: 101 acute, 25 gangrenous and 15 perforated appendices). Mean C-reactive protein levels at admission were 25.1, 55 and 66.7 mg/L, respectively in these histological subgroups and 14.9 mg/L in the non-appendicitis group (p < 0.001). The total white cell count was also statistically significant. Both tests were equally valuable in patients whose symptoms had a duration of more than 12 hours. The total white cell count was more valuable in patients with less than 12 hours of symptoms. The likelihood ratio for appendicitis was 2.72 for a C-reactive protein greater than 20 mg/l and a total white cell count above 15,000/mm3. The likelihood ratio of not having appendicitis was 0.37 when both tests were below these values.

CONCLUSIONS

Measurement of C-reactive protein is useful in the diagnosis of acute appendicitis, mainly in cases with more than 12 hours of evolution. The combined tests improved the predictive values.