[Use of the rapid antigen detection test in group A streptococci pharyngitis diagnosis in Tunis, Tunisia]. / Utilisation d'un test de diagnostic rapide des angines à streptocoque bêta-hémolytique du groupe A, auprès d'un échantillon d'enfants à Tunis, Tunisie.

The aims of this study were to determine the contribution of commercial rapid antigen detection test (RADT) in the rapid diagnosis of pharyngitis caused by group A streptococci. A total of 292 children with pharyngitis was included. A duplicate throat swabs was taken simultaneously from each patient. One of them was used for RADT achievement and the other for culture. When cultures were positive, a semi-quantitative evaluation was done. Throat culture and RADT were positive in 59 and 72 cases respectively. Fifty four specimens were positive simultaneously with RADT and culture and 215 specimens were negative using both methods. Eighteen specimens were positive only with RADT, 5 of them were treated by amoxicillin. Regarding to the group of patients with a negative RADT and a positive culture (5 cases), all of them had a culture evaluation at "+" or "++". Specificity and sensibility of the RADT were 92.2% and 91.5% respectively. RADT use by physicians can reduce antibiotic prescription among paediatric population. Because of the high specificity of RADT, therapeutic decisions can be made on the basis of a positive test.