Abstract
In 107 patients with lower respiratory tract infections, counterimmunoelectrophoresis (CIE) of blood and sputum, bacterial cultures of blood, sputum and nasopharyngeal secretion, and enzyme-linked immunosorbent assay (ELISA) for antibody determination were performed, with special reference to pneumococci and Haemophilus influenzae. For pneumococci CIE of sputum was superior to culture especially in antibiotic-treated patients. The clinical significance of a positive CIE of sputum was supported by close correlation to significant antibody increase. The usefulness of CIE regarding H. influenzae was more difficult to evaluate.