[Diagnosis of streptococcal pharyngitides].

Tonsillitis and pharyngitis are highly frequent infections in Spain with multiple causes, especially viruses. Etiologic diagnosis of pharyngitis is only important in Streptococcus pyogenes or group A beta-hemolytic streptococcal infections because antibiotic therapy is mandatory to prevent further complications, especially acute rheumatic fever. Diagnosis has classically been based on bacterial isolation from throat swabs. There are no standardized methods for this culture in terms of culture medium, incubation atmosphere or the identification tests to be performed. Currently, a large number of commercial reagents are available, which, through different immunological techniques, allow direct antigen detection in the clinical sample. Most of these products show good sensitivity and specificity values, with the added advantage of providing a rapid result, especially if they are performed at points of care. Many guidelines for the management of patients with pharyngitis and tonsillitis are available. Nevertheless, as antigen detection results can vary in each center according to the indications and the care taken in sample extraction, the method chosen should be evaluated before implementation.