Rapid detection of pneumococcal antigens in sputa in patients with community-acquired pneumonia by coagglutination.

This paper introduces the clinical use of coagglutination as a method for the rapid detection of pneumococcal antigens in patients with community-acquired pneumonia and compares it with the sputum Gram stain and culture methods. Among 105 patients, 50 (48%) were diagnosed as having pneumococcal pneumonia by at least one of the three methods. Of 95 sputa tested, 44 (46%) were found to be positive by the coagulation test, 26 (27%) by Gram staining and only 16 (17%) by the bacterial culture method. The rate of detection of pneumococcal antigens was thus greater with coagulation than with either of the other two methods. The differences were very significant (both P less than 0.01). Our study indicates that the advantages of coagglutination over the traditional bacteriological methods are its speed, sensitivity, convenience and also its relative independence of antibiotic therapy. It thus provides a new dimension in the aetiological diagnosis of pneumococcal pneumonia.