Rapid diagnosis of group A strep pharyngitis in the emergency department.

Two ten-minute rapid tests for diagnosing Group A streptococcal pharyngitis in 147 emergency department patients with a complaint of sore throat were evaluated using positive throat cultures as the marker for disease. Treatment was initiated solely on the basis of clinical judgment. Sensitivity and specificity were 78% and 93%, respectively, for the rapid test and 69% and 56%, respectively, for clinical judgment. The rapid test was significantly better than clinical judgment alone in determining the presence of disease (P less than .05). The predictive values of the positive and negative and were 78% and 93%, respectively, for the rapid test and 38% and 85%, respectively, for clinical judgment. In the ED setting in which adequate followup is difficult, the rapid test can identify more accurately than can clinical judgment alone those patients who need therapy.