What is the sensitivity and specificity of rapid strep tests for the diagnosis of group A streptococcal (GAS) infections?

Updated: Apr 08, 2021
  • Author: Zartash Zafar Khan, MD, FACP; Chief Editor: Pranatharthi Haran Chandrasekar, MBBS, MD  more...
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Numerous studies have demonstrated that the currently available rapid streptococcal tests have a sensitivity of 70-90% compared with standard throat cultures. In contrast to their relatively low sensitivity, the specificity of these rapid tests has consistently been 90-100%. Therefore, if a rapid streptococcal test result is positive, a culture is not necessary, and appropriate antibiotic therapy can be immediately initiated. However, when a negative rapid test result is encountered, a standard throat culture should always be obtained.

In one study, rapid antigen detection sensitivity and specificity were found to be 64.6% and 96.79%, respectively. The positive predictive value was 80.95% whereas negative predictive value was 92.82%. [29]  

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