Diagnosis
Key Points
����Swabbing the throat and testing for GAS pharyngitis by rapid antigen
detection test (RADT) and/or culture should be performed because the
clinical features alone do not reliably discriminate between GAS and viral
pharyngitis except when overt viral features like rhinorrhea, cough, oral
ulcers and/or hoarseness are present.
������ In children and adolescents, negative RADT tests should be backed up by a throat
culture (SR-H). Positive RADTs do not necessitate a back-up culture because they are
highly specific (SR-H).
����Routine use of back up throat cultures for those with a negative RADT
is not necessary for adults in usual circumstances because there is a
low incidence of GAS pharyngitis in adults and the risk of subsequent
acute rheumatic fever is generally exceptionally low in adults with acute
pharyngitis (SR-M).
Physicians who wish to��ensure they are achieving maximal sensitivity in diagnosis may
continue to use conventional throat culture or to back up negative RADTs.
����Anti-streptococcal antibody titers are not recommended in the routine
diagnosis of acute pharyngitis since they reflect past but not current events
(SR-H).
����Testing for GAS pharyngitis usually is not recommended for children or
adults with acute pharyngitis with clinical and epidemiologic features that
strongly suggest a viral etiology (e.g., cough, rhinorrhea, hoarseness, and
oral ulcers) (SR-H).
����Diagnostic studies for GAS pharyngitis are not indicated for children
< 3 years old because acute rheumatic fever is rare in these children
and the incidence of streptococcal pharyngitis and the classic presentation
of streptococcal pharyngitis are uncommon in this age group.
Selected children < 3 years old who have other risk factors such as an older sibling with GAS
infection may be considered for testing (SR-M).
����Follow-up post-treatment throat culture or RADT is not recommended
routinely but may be considered in special circumstances (SR-H).
����Diagnostic testing or empiric treatment of asymptomatic household
contacts of patients with acute streptococcal pharyngitis is not routinely
recommended (SR-M).
