Evaluation of a rapid test to detect Streptococcus group A

Rapid tests for the detection of group A beta-hemolytic streptococcus (GABHS) directly from a throat swab have become very popular. Previous studies have reported an antigen test sensitivity of 55-95% and a specificity of 88-100%. The present study evaluates the reliability of one rapid test in detecting GABHS (PathoDx). A total of 164 throat swab specimens was taken. GABHS was isolated on the culture in 37 (22.5%), and the rapid test was positive in 60 (36.6%). The sensitivity of the rapid test was 86.5% and the specificity 80%. Of the 60 positive rapid test results, 28 (47%) were false positive and the positive predicted value was 53%. We conclude that results obtained using rapid test kits should be compared to throat cultures in order to determine the reliability of such kits in specific clinical settings.