[Reliability and general practice value of 2 rapid Streptococcus A tests].
Rapid streptococcal-A-antigen detection assays have good specificity (over 90 percent) but moderate sensitivity (between 80 and 90 percent), when the tests are compared with a standard throat culture. Contradictory results have been found for one of the more recent tests, the optical immune assay Strep A OIA MAX, while for 6 years, we have been using the immune assay Strep A Plus. Results of the optical immunoassay and the conventional immune assay Strep A Plus were compared in 65 patients with acute pharyngitis. A standard culture was used as reference and confirmed by enhanced broth culturing and nucleic acid hybridization assay (Gen-Probe) when the two detection assays produced contradictory results. While both assays were equally sensitive (78.3%), Strep A OIA MAX and Strep A Plus had a similar specificity of 95.2% and 100%, respectively. Four and nine steps were required for Strep A Plus and for Strep A OIA MAX test procedures, respectively with results being available in 4-5 min and in 9-10 min, respectively. We conclude that both rapid immunoassays have a similar reliability while the handling of the Strep A Plus is much simpler than the handling of the Strep A OIA MAX. Neither rapid immunoassays are sensitive enough to eliminate the need for backup cultures.
Schmuziger
N
N
HNO-Universitätsklinik, Kantonspital Basel, Germany. nschmuziger@uhbs.ch
Schneider
S
S
Frei
R
R
D000293:Adolescent; D000328:Adult; D000368:Aged; D000942:Antigens, Bacterial / Q000032:analysis; D001431:Bacteriological Techniques; D002648:Child; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques / Q000379:methods*; D008297:Male; D008875:Middle Aged; D010612:Pharyngitis / Q000175:diagnosis*; D011933:Reagent Kits, Diagnostic; D012680:Sensitivity and Specificity; D013290:Streptococcal Infections / Q000175:diagnosis*; D013297:Streptococcus pyogenes / Q000276:immunology; D014069:Tonsillitis / Q000175:diagnosis*
D000942:Antigens, Bacterial; D011933:Reagent Kits, Diagnostic