Serum C-reactive protein in the differential diagnosis of childhood meningitis

Background: Although determination of serum C-reactive protein (CRP) is considered one of the most useful tests for differentiating between bacterial and aseptic meningitis, its diagnostic accuracy in comparison with other laboratory parameters is yet to be further evaluated. Methods: A total of 192 pediatric cases, aged between 2 months and 14 years, comprising patients with bacterial meningitis (n=66) and aseptic meningitis (n=126), were retrospectively analyzed on the basis of data from the initial examination. The area under the best fit binormal curve of the receiver operating characteristics (Az) for CRP was determined and compared with that for several other analytic parameters, including white blood cell count and erythrocyte sedimentation rate of peripheral blood, standard cerebrospinal fluid analysis variables and the combination test (probability of acute bacterial meningitis (pABM)) derived from Hoen's model. Results: Compared with each of the other variables, the Az for serum CRP (0.97+/-0.02) was found to be significantly greater (P <0.01) for all except pABM (0.99+/-0.01; P >0.05). False-negative cases among the CRP test results were found to have been examined too early. Conclusions: The diagnostic accuracy of a single CRP determination was found to be equivalent to that of the most effective combination test. Patients with meningitis in whom serum CRP values are determined at least 12 h after the onset of fever and are <2 mg/dL are far less likely to have bacterial meningitis.