Strep A Test utilizes two-site sandwich immunoassay technology for the detection of Group A Streptococcal antigen. The test consists of a membrane strip that was precoated with rabbit anti-Strep A antibody on the test band region and goat anti-rabbit antibody on the control band region.
A colored rabbit anti-Strep A antibody-colloidal gold conjugate pad is placed at the end of the membrane. During testing, the Strep A antigen is extracted from the throat swab using Extraction Reagents. The test strip is then immersed in the extracted sample. The mixture then moves chromatographically on the membrane to the immobilized rabbit anti-Strep A antibody at the test band region. If the Strep A antigen is present in the specimen, a colored sandwich of solid-phase/Strep A antigen/gold conjugate is formed on the test band region.
The absence of the colored band at the test band region indicates a negative result. Regardless of the presence of Strep A antigen, as the extracted mixture continues to move laterally across the membrane to the immobilized goat anti-rabbit antibody control band region, a colored band at the control region will always appear. The presence of this colored band serves as 1) verification that sufficient volume has been added, 2) verification that proper flow is obtained, and 3) reagent control.