Performance Characteristics - Gima STREP A Manual De Uso

13
5. As with all diagnostic tests, all results must be interpreted together with other clinical information
available to the physician.
EXPECTED VALUES
Approximately 15% of pharyngitis cases in children ages 3 months to 5 years are caused by
Group A beta-hemolytic Streptococcus.
Strep throat infection is about 40%.
temperate climates. 3

PERFORMANCE CHARACTERISTICS

Sensitivity and Specificity
Using three medical centers and a reference laboratory for evaluation, a total of 758 throat
swabs were collected from pediatric and adult patient populations exhibiting symptoms of
pharyngitis. Each swab was rolled onto a Group A selective (GAS) blood agar plate, and then
tested by the Strep A Twist Rapid Test Device (Throat Swab). The plates were further streaked
for isolation, and then incubated at 37°C with 5-10% CO2 and a Bacitracin disk for 18-24 hours.
The negative culture plates were incubated for an additional 18-24 hours. Possible GAS colonies
were subcultured and confirmed with a commercially available latex agglutination grouping kit.
Of the 758 total specimens, 492 were found to be negative by culture and 266 were found to be
positive by culture. Two out of the 758 specimens yielded invalid results and are therefore excluded
from the table.
6 In school-aged children and adults, the incidence of
7
This disease usually occurs in the winter and early spring in
ENGLISH