Streptococcal pharyngitis--rapid diagnosis by Gram stain.

Group A beta-haemolytic streptococci were isolated from 51 (9.8%) of 519 patients with pharyngitis. Throat culture results showed the mean sensitivity, specificity and predictive value of a positive Gram-stained smear of pharyngeal secretions as 70%, 89% and 69%. The data suggest that Gram staining of a smear directly from the swab is as accurate as and more speedy than a culture from the pharyngeal secretion for diagnosis of streptococcal pharyngitis.