Use of Counter and rocket immunoelectrophoresis in acute respiratory infections due to Streptococcus pneumoniae.

The use of Counter immunoelectrophoresis (CIE) for the detection of pneumococcal capsular antigen in the sputum and serum of patients suffering from acute respiratory infections is described. The CIE of sputum gave positive results in 224 (99%) out of 225 samples in which Streptococcus pneumoniae was isolated by cultural techniques, and in 23 (9%) out of 262 samples in which no or other potential pathogens had been isolated. In the detection of capsular antigen in serum, CIE was positive in 32 (35%) out of 92 pneumonia cases and was associated with an increase in mortality.