Assessment of a rapid urinary antigen detection by an immunochromatographic test for diagnosis of pneumococcal infection in children

Abstract

The aim of the study was to evaluate the Binax Now rapid immunochromatographic test (ICT) for the detection of Streptococcus pneumoniae urinary antigen in children suffering from potentially pneumococcal infections. A total of 287 patients, with a median age of 34.9 months and divided into 3 groups, were studied; the first group of patients with a suspected pneumococcal infection ( n = 112), the second group with infectious symptoms nonsuggestive of a pneumococcal infection ( n = 54), and the third group was composed of asymptomatic children ( n = 121). In group 1, sensitivity of ICT was 100% and specificity was 55.9% (95% confidence interval, 44.1– 67.7). Forty-six (85.1%) patients from the second group were true negatives. Twenty-five (20.7%) patients from the third study group were nasopharyngeal pneumococcal carriers, and the ICT was positive in 13 carriers (10.7%). The high sensitivity level of ICT in our study indicates that a negative test could rule out a pneumococcal infection, contrasted with a poor specificity.