Streptococcal pharyngitis: evaluation of diagnosis by gram stain in a pediatric acute care clinic.

Clinical prediction of streptococcal pharyngitis at the initial visit is often difficult. The applicability of the gram stain in the initial assessment of streptococcal pharyngitis was evaluated by comparing gram stain with ultimate culture results. Positive gram stains showed polymorphonuclear cells and typical gram-positive cocci. Thirty-one physicians rotating through the Acute Care Clinic of a county teaching hospital participated in the evaluation. The sensitivity, specificity, and predictive value of a positive test (PVP) were 62 per cent, 70 per cent, and 47 per cent, respectively. These results were compared to a clinical algorithm and to the results of a group with more expertise in the technique. It is concluded that the gram-stained smear of pharyngeal secretions does not appear to be a practical tool for the diagnosis of streptococcal pharyngitis in a busy pediatric emergency unit of a teaching hospital.