FIGURE 74.4 Diagnostic approach when findings are clinically suggestive for mononucleosis WBC, white blood cell; IM, infectious mononucleosis; EBV, Epstein–Barr virus Ultimately, most children will have a mildly to moderately inflamed pharynx but no specific etiologic diagnosis based solely on the history and physical examination The local, recent incidence of group A streptococcal pharyngitis is an important predictor of strep throat among symptomatic patients Integration of real-time biosurveillance data with the electronic health record has the potential to facilitate improved diagnosis of strep throat Although certain symptoms and signs favor streptococcal infection, none is conclusive Thus, obtaining a rapid test (latex agglutination or optical immunoassay) for group A streptococci, followed by a culture, if negative, is prudent Rapid tests are most helpful when a positive result is obtained because specificity of the tests is high; however, a negative test result does not exclude streptococcal infection reliably, although some authorities would be satisfied with a negative optical immunoassay alone About 10% to 20% of children are carriers of group A streptococci Testing these