patients for strep throat when they have only nonspecific symptoms like abdominal pain or prominent upper respiratory symptoms, may result in a positive test, leading to unnecessary use of antibiotics, and contributing to increased side effects, costs, and resistance While no sign or symptom is specific or sensitive enough to diagnose GAS, a number of clinical decision rules (CDRs) have been developed to aid diagnosis and limit unnecessary diagnostic testing The Centor criteria are perhaps the best known and consist of four signs, with one point each given for fever, tonsillar exudates, tender anterior cervical nodes, and absence of cough Patients with a score of or are presumed to have viral pharyngitis and require no further testing, whereas higher scores are progressively more likely to reflect GAS infection The Modified Centor score (McIsaac score) adjusts for patient age, reflecting the higher incidence of GAS among children age to 15 years To prevent the delayed sequela of rheumatic fever, the accurate diagnosis of streptococcal pharyngitis assumes great importance Generally, symptomatic therapy suffices in the patient with a negative rapid test, although the physician may elect to initiate therapy, usually with a penicillin (penicillin V or amoxicillin) but occasionally with a cephalosporin or macrolide, while awaiting the results of the throat culture in selected cases with highly suggestive clinical features It is worth noting that the macrolides will not treat Fusobacterium, which rarely causes sore throat but is the primary pathogen in Lemierre syndrome Suggested Readings and Key References Centor RM, Witherspoon JM, Dalton HP, et al The diagnosis of strep throat in adults in the emergency room Med Decis Making 1981;1(3):239–246 Fine AM, Nizet V, Mandl KD Improved diagnostic accuracy of group A streptococcal pharyngitis with use of real-time biosurveillance Ann Intern Med 2011;155(6):345–352 Fine AM, Nizet V, Mandl KD Large-scale validation of the Centor and McIsaac scores to predict group A streptococcal pharyngitis Arch Int Med 2012;172(11):847–852 Fine AM, Nizet V, Mandl KD Participatory medicine: a home score for streptococcal pharyngitis enabled by real-time biosurveillance Ann Intern Med 2013;159(9):577–583 Fleisher GR, Lennette ET, Henle G, et al Incidence of heterophil antibody responses in children with infectious mononucleosis J Pediatr 1979;94(5):723–728