Dr. Corwin is concerned about the possible poor sensitivity of pharyngeal culture compared with the ASLO titre. The test characteristics of pharyngeal culture when compared with a variety of other tests have varied in the literature, as we reviewed in our article and its appendix. Probably because ASLO assessment takes at least a week and thus cannot be used for treatment decisions in the clinical setting, there is unfortunately little information regarding ASLO titers in a group of patients "suspicious" for streptococcal pharyngitis or in patients receiving rapid immunoassay testing. This lack of data made it difficult for us to use ASLO as our gold standard. Furthermore, some of the issues regarding sensitivity may be reduced with careful attention to culture technique (1), and recent studies using polymerase chain reaction to assess both immunoassays and pharyngeal culture suggest that test performance of culture is much better than the 70% sensitivity cited by Dr. Corwin (2). For these reasons, although we agree that it is less than ideal, we and authors of similar studies have chosen to use pharyngeal culture as a gold standard.

Drs. Cohen and Centor report some interesting unpublished data (3) on the patient utility for sore throat and are concerned that our analysis of patients with severe pharyngitis (that is, those who had positive results on 3 to 4 Centor criteria) did not take into account the possibility of a different utility for these patients. Although our estimates for the sequelae of sore throat were taken from a patient survey that compared them with sore throat (4), our utility estimate for pharyngitis was certainly limited by the lack of information in the literature on patients' utilities for sore throat. We note that our utility estimate for our base-case scenario was identical to that reported by Drs. Cohen and Centor for "mild" pharyngitis. We agree with Drs. Centor and Cohen that patient disutilities vary for many disease states and are likely to be higher on average in patients with more severe symptoms and signs of pharyngitis. In pharyngitis, a disease in which sequelae are rare, individual patient disutilities should be carefully considered and may indeed drive decision making. The typical patient encountered in primary care has a less severe sore throat, so the incorporation of Rousculp's findings would not change our main, baseline findings. Empirical therapy without testing was neither the most effective nor least expensive strategy at any prevalence of group A ß-hemolytic streptococcal infection typically seen in adult populations.