Optical immunoassay test for group A beta-hemolytic streptococcal pharyngitis. An office-based, multicenter investigation.
OBJECTIVE
To compare the accuracy of an optical immunoassay (OIA) for the rapid diagnosis of group A streptococcal pharyngitis with blood agar plate (BAP) culture.


METHODS
Blinded comparison with criterion standard.


METHODS
A total of 6 private pediatricians' offices, 3 in Connecticut and 3 in Chicago, III.


METHODS
A total of 2113 consecutive patients with acute pharyngitis, 983 in Connecticut and 1130 in Chicago.


METHODS
The sensitivities and specificities of OIA and BAP culture (both performed and interpreted in the office) were determined using a research laboratory's interpretation of a combination of BAP culture and Todd-Hewitt broth (THB) culture of transport tube pledget as criterion standard.


RESULTS
Among patients in Connecticut, the sensitivities of the OIA and BAP culture were 94% and 89%, respectively (P=.004), while the specificities were 96% and 99%, respectively (P=.001). Among patients in Chicago, the sensitivities of the OIA and BAP culture were 79% and 72%, respectively (P<.001), while the specificities were 89% and 99%, respectively (P<.001). In each of the 6 pediatricians' offices, the OIA was more sensitive than the BAP culture. Combining the data from Connecticut and Chicago, the overall sensitivities of the OIA and BAP culture were 84% and 78%, respectively (P<.001), while the specificities were 93% and 99%, respectively (P<.001).


CONCLUSIONS
The results of this comprehensive office-based investigation suggest that with adequately trained personnel, negative OIA test results may not always need to be routinely confirmed with BAP cultures.
Gerber
M A
MA
Department of Pediatrics, University of Connecticut School of Medicine, Farmington, USA.
Tanz
R R
RR
Kabat
W
W
Dennis
E
E
Bell
G L
GL
Kaplan
E L
EL
Shulman
S T
ST
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D001431:Bacteriological Techniques; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007118:Immunoassay / Q000379:methods*; D007223:Infant; D008297:Male; D009819:Office Visits; D010612:Pharyngitis / Q000382:microbiology*; D012680:Sensitivity and Specificity; D013290:Streptococcal Infections / Q000175:diagnosis*; D013297:Streptococcus pyogenes / Q000302:isolation & purification*