[Basic and clinical evaluation of the new rapid diagnostic kit for detecting group A streptococci with the...

Basic and clinical performance of a new diagnostic kit that detects Group A Streptococci by an immunochromatographical method, QuickVue Dipstick Strep A (Quidel Corporation; San Diego, CA) were evaluated. In basic specificity study, the QuickVue Dipstick Strep A showed positive reaction only to group A Streptococci strains among 34 strains of 10 species of bacteria. In detection limit study, the QuickVue Dipstick Strep A had a capacity to detect Group A Streptococci in 1.0 x 10(4); cfu/ml (1.0 x 10(3) cfu/test). This sensitivity was about 6 times higher than that of the existing similar immunochromatographical test, STREP A TESTPACK Plus (TESTPACK, Abbott Japan, Tokyo). In clinical study compared with bacterial culture test using 100 patients' throat swab specimens, the QuickVue Dipstick Strep A showed a sensitivity of 94.4% (34/36), a specificity of 100% (64/64) and an accuracy of 98% (98/100). Furthermore in correlation study with the reference test, TESTPACK, the QuickVue Dipstick Strep A showed 100% agreement (34 positive and 66 negative specimens). As the QuickVue Dipstick Strep A has several advantages as not only simple operation, rapid reaction and good performance but also easy storage (under room temperature), compact size and minimum waste products, we conclude that this new test is useful as Point-of-Care Testing kit and plays a peripheral role in the diagnosis of Group A Streptococci infection and pertinent medical treatment by antibacterial agents.