Comparison of TestPack Strep A test kit with culture technique for detection of group A streptococci.
Results obtained with Abbott Laboratories TestPack Strep A (TPSA), a 7-min enzyme immunoassay method, were compared with culture results to measure the ability of this assay to detect group A streptococci directly from 365 throat swabs. Our study demonstrated a sensitivity of 90.0% and a specificity of 97.4% for TPSA compared with cultures incubated for 48 h. The positive and negative predictive values of this assay versus the culture method were 92.8 and 96.3%, respectively. If specimens that provided fewer than 10 colonies per plate of group A streptococci are eliminated from the data, the sensitivity is increased to 95.6%. Additionally, 10 group A and 40 non-group A streptococcal isolates were tested directly with TPSA for the ability to distinguish group A from non-group A streptococci. All 50 isolates were correctly identified (100% accuracy). TPSA is a rapid, accurate, and easy-to-interpret method for detection and confirmation of group A streptococcal antigen directly from throat swabs and pure culture isolates.
D000942:Antigens, Bacterial / Q000032:analysis*; D006801:Humans; D007124:Immunoenzyme Techniques; D010612:Pharyngitis / Q000175:diagnosis*; D010614:Pharynx / Q000382:microbiology*; D011933:Reagent Kits, Diagnostic; D013290:Streptococcal Infections / Q000175:diagnosis*; D013297:Streptococcus pyogenes / Q000276:immunology / Q000302:isolation & purification*
D000942:Antigens, Bacterial; D011933:Reagent Kits, Diagnostic