General information about this test:
OSOM® Strep A Test is a rapid chromatographic immunoassay for qualitative detection of Streptococci group A from throat swabs. OSOM® Strep A is also suitable for confirmation of presumptive Group A Streptococcal colonies recovered from culture. OSOM® Strep A Test is intended for professional in vitro diagnostic use only.

Reagents and material supplied:

• 50 Test Sticks
• 50 Test Tubes
• 50 Sterile Swabs
• 1 Reagent 1 (2 M Sodium Nitrite)
• 1 Reagent 2 (0.3 M Acetic Acid)
• 1 Positive Control (Nonviable Group A Streptococci, 0.1% Sodium Azide)
• 1 Negative Control (Nonviable Group C Streptococci, 0.1% Sodium Azide)
• 1 Directional Insert

Test time: 5 min

Performance characteristics:
The diagnostic specificity and sensitivity of OSOM® Strep A Test were determined by comparison with other commercially available rapid assays applied to cultures (started from the same samples).

Sensitivity: 96.0%
Specificity: 97.8%
Overall agreement: 97.3%

As a means of confirmation of the identity of Group A Streptococcus on blood agar plates the OSOM® Strep A Test demonstrates:

Sensitivity: 100%
Specificity: 100%

Test principles:
The OSOM® Strep A Test is a qualitative rapid immunoassay for the detection of Group A Streptococci antigens from throat swabs. The OSOM® Strep A Test uses color immunochromatographic dipstick technology with rabbit antibodies coated on the nitrocellulose membrane. Before testing, highly specific carbohydrate antigens are extracted from a throat swab. The Test Stick is then placed in the extraction mixture and the mixture migrates along the membrane. Group A Streptococcus antigens, if present in the extraction mixture, bind to anti-Group A Streptococcus antibodies conjugated to colored particles, forming antigen-antibody complex. Further, this complex binds to anti-Group A Streptococcus capture antibodies thus producing blue coloration in the Test Line region.The red coloration in the Control Line is an internal positive procedural control.

Clinical significance:
Upper respiratory tract infections are very frequently associated to Group A Streptococci. Seasonal variations are characteristic to Group A Streptococci-caused pharyngitis – it is most prevalent during winter and early spring. The highest incidence of this disease is found in crowded populations such as military bases and in school-age children. Early diagnostics of Group A Streptococcal pharyngitis aids prevention of more severe symptoms and complications such as such as Scarlet fever, rheumatic fever and glomerulonephritis.