Diagnosis of whooping cough--a comparison of culture, immunofluorescence and serology with ELISA.

Three methods for diagnosis of whooping cough--culture, immunofluorescence (IF) technique on nasopharyngeal secretion and serology with ELISA--were compared. 52 patients with symptoms of upper respiratory tract infection, which could not exclude pertussis as a differential diagnosis, were investigated. Pertussis infection was confirmed in 30 patients. Of these 16 (53%) were found by culture, 19 (63%) by IF and 28 (93%) by serology. It is concluded that IF analysis of nasopharyngeal secretion is a valuable tool for rapid diagnosis of whooping cough with a sensitivity similar to that of culture. Serodiagnosis with ELISA added a significant number of positive patients in which culture and IF were negative.