Open AccessPerformance of the tandem ICON strep A® enzyme immunoassay system for detection of group a streptococci from oropharyngeal swabs
Author(s) -
Kellogg James A.,
Bankert David A.,
Levisky John S.
Publication year - 1988
Publication title -
journal of clinical laboratory analysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.536
H-Index - 50
eISSN - 1098-2825
pISSN - 0887-8013
DOI - 10.1002/jcla.1860020405
Subject(s) - throat , pharyngitis , throat culture , group a , medicine , immunoassay , predictive value , microbiology and biotechnology , agar , streptococcus , immunology , bacteria , biology , surgery , antibody , genetics
The Tandem ICON Strep A® (TISA Hybri‐tech, Inc.) was compared to culture for detection of group A streptococci, using throat swabs obtained from patients with symptoms of pharyngitis. Each swab was first inoculated to a 5% sheep blood agar plate and then tested for streptococcal antigen using the TISA. Cultures were incubated anaerobically at 35°C for 36 to 48 hours unless positive following overnight incubation. Group A streptococci were recovered in culture and serologically identified from 163 (21.0%) of the 776 swabs processed. The sensitivity and specificity of the TISA were 76.7% and 96.4%, respectively, whereas the predictive values of positive (PVP) and negative (PVN) results were 85.0% and 94.0%, respectively. However, TISA specificity ranged from 93.6% in one of 3 lots tested to 99.1% in another (P < 0.005). The PVP of the former lot was 76.3%, whereas that of the latter was 95.6% (P < 0.005). The relative lack of sensitivity and lot‐to‐lot variation observed with the TISA in this study indicate that the product is not a suitable alternative to a competently performed throat culture.