Rapid diagnosis of invasive pneumococcal disease in pediatric population

• We evaluate the Binax NOW pneumococcal antigen test in pleural fluids and cerebrospinal fluids.
• The Binax NOW results were compared with those obtained by real-time PCR.
• The sensitivity and specificity of Binax NOW was 88% and 72.5%, respectively.
• Binax NOW allowed us to identify more S. pneumoniae isolates than culture alone.

The aim of this study was to evaluate the Binax NOW immunochromatographic pneumococcal antigen test for the identification of Streptococcus pneumoniae in pleural and cerebrospinal fluids from children with suspected invasive pneumococcal disease. The results were compared with those obtained by PCR. Binax NOW was applied to these samples as recommended by the manufacturer for urine and cerebrospinal samples. Detection of pneumococcal DNA was performed by real-time PCR assay targeting the autolysin gene (lytA). Of the 199 samples analyzed, 131 were positive by both Binax NOW and lytA PCR, and 36 samples were negative by both techniques. Using the real-time PCR as a comparative method to the Binax for the detection of S. pneumoniae, the sensitivity and specificity of Binax NOW was 88% and 72.5%, respectively. Of the 145 positive samples analyzed by Binax NOW, 119 showed intense coloring of the sample line and 26 showed weak intensity. Conventional culture is the most common method in clinical settings, but Binax NOW is an easier and faster test for identifying S. pneumoniae in pleural and cerebrospinal fluids from children with suspected invasive pneumococcal disease.