Liposome immunoassay for rapid identification of group A streptococci directly from throat swabs.

The Q Test Strep (Becton Dickinson and Co., Franklin Lakes, N.J.) is a new solid-phase liposome immunoassay for the rapid diagnosis of group A beta-hemolytic streptococcal pharyngitis. Compared with blood agar plate cultures, the Q Test Strep had a sensitivity of 91%, a specificity of 83%, a positive predictive value of 88%, and a negative predictive value of 87%. Liposome technology can be used to facilitate the rapid diagnosis of group A beta-hemolytic streptococcal pharyngitis.