A new coagglutination test for detecting pneumococcal C-polysaccharide.

A new coagglutination test (PnC-CoA) for detecting pneumococcal C-polysaccharide (PnC) was compared with a commercial kit for detecting capsular polysaccharide using sputum samples from 105 patients with pneumonia. The sensitivity obtained with PnC-CoA was 95.8% and with the commercial kit 83.3%; the specificity was 96.5% and 91.2%, respectively. The PnC-CoA is simple to perform and it is a rapid, sensitive and specific test for detecting Streptococcus pneumoniae in sputa from adult patients with pneumonia.