[Diagnosis of sore throat. A multipractice study of 3 different ways of antigenic determination for detection of group A streptococci in throat swabs].

During five months in the winter of 1992/1993, 34 general practitioners (GPs) from 18 offices participated in a clinical testing of three group A streptococcal antigen detection test (ADT) kits (Abbott TestPack Strep A Plus (Abbott), Concise Strep A, Hybritech (Concise) and Kodak SureCell Strep A (Kodak)). The GPs obtained duplicate throat swabs, one for processing with the ADT kit, the other for culture reference at The Streptococcus Laboratory (Bacteriological Department, Statens Seruminstitut, Copenhagen). A total of 1389 patients were enrolled in the study, thirty percent of whom were infected by group A streptococci. The following results were obtained: Abbott: Sensitivity: 76%, specificity: 99%, positive predictive value: 97%, negative predictive value: 91%. Concise: Sensitivity: 82%, specificity: 95%, positive predictive value: 86%, negative predictive value: 92%. Kodak: Sensitivity: 84%, specificity: 87%, positive predictive value: 73%, negative predictive value: 93%. As a follow-up to the main study, each GP filled in a questionnaire, stating his opinion about the investigated ADT kit. Considering the practical handiness, Concise scored higher than Abbott, which in turn scored higher than Kodak. In conclusion, Abbott and Concise are recommended for the diagnosis of group A streptococcal pharyngotonsillitis in general practice.