TABLE 2.

Sensitivities, specificities, and predictive values for Directigen rapid antigen immunoassay and LightCycler PCR assay compared to the results of culture for detection of GAS from throat swabsa

Type of assaySensitivity (%)Specificity (%)Positive predictive value (%)Negative predictive value (%)
Directgen antigen immunoassay55 (41, 68)b99 (98, 100)97 (83, 100)93 (90, 95)
LightCycler PCR assay93 (82, 98)b98 (96, 99)88 (77, 95)99 (97, 100)
  • a The prevalence rate of positive cultures was 14.3%. Values in parentheses are 95% confidence intervals.

  • b Signficantly different by McNemar's test (P < 0.001).