What is the criterion standard diagnostic test for streptococcal pharyngitis (strep throat)?

Updated: Sep 07, 2018
  • Author: Zartash Zafar Khan, MD, FACP; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Answer

Because pharyngitis and tonsillitis may result from various infectious etiologies other than S pyogenes infection, the diagnosis should be confirmed. Throat culture remains the criterion standard diagnostic test for streptococcal pharyngitis.

If performed correctly, culture of a single throat swab on a blood agar plate yields a sensitivity of 90-95% for the detection of group A streptococci (GAS) in the pharynx. [2, 28]

Although some throat culture results are false-positive (eg, they do not reflect acute infection but, rather, symptomatic carriage), all patients with positive culture results are treated with antibiotics.


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