Identifying the pneumococcal antigen in the cephalorachidian fluid using the immunochromatographic method

We determined the accuracy of the NOW S. pneumoniae Urinary Antigen Test (Binax, Portland, ME, USA) when it comes to detecting the pneumococcal antigen in the cephalorachidian fluid. 30 patients under suspicion of acute meningitis were tested for the presence of pneumococcal antigen in the cephalorachidian fluid using both the latex and the NOW S. Pneumoniae Urinary Antigen test. We also performed direct microscopic examination and insemination on solid and fluid culture media of the cephalorachidian fluid. Samples of cephalorachidian fluid taken from 5 patients (smear and in 2 cases in cultures) tested positive for pneumococcus. Both the NOW and the latex test were positive in all 5 cases (with a 100% sensitivity). In the rest of the cases the NOW test was negative (with a 100% specificity). By contrast, the latex test was positive in 2 cases of meningitis of other aetiology (with a 92% specificity). The NOW test allows a rapid and correct diagnosis for pneumococcal meningitis, determining the choice of appropriate treatment.