Princeton Biomedical 34125 - Status Strep A Flip (25 Tests)(Cassette) (waived)

Status Strep A Flip Intended Use

The Status Strep A Flip is a rapid immunochromatographic assay for the qualitative detection of group A streptococcal antigen directly from throat swab specimens. The test is intended for use in physicians offices, hospitals and clinical laboratories as an aid in the clinical diagnosis of group A streptococcal infection.

Summary and Explanation

Group A streptococcus is one of the most significant human pathogens causing acute pharyngitis, tonsillitis, impetigo, and scarlet fever (1). It is very important to differentiate streptococcal infection from other etiologic agents (e.g., viral, mycoplasmal, or chlamydial) so that appropriate therapy may be initiated. Classical methods for identification require 1848 hours culture time for throat swab specimens or other exudates to produce results showing bacitracin susceptible beta-hemolytic streptococci. Rapid diagnosis and timely treatment of group A streptococcal pharyngitis infections will reduce the severity of symptoms and further complications such as rheumatic fever and glomerulonephritis (2-6).

Principle

Status Strep A Flip is a rapid immunochromatographic assay for the qualitative detection of group A streptococcal antigen directly from throat swabs. The Status Strep A Flip test involves the chemical extraction of group A streptococcal antigen followed by solid-phase immunoassay technology for the detection of extracted antigen. In the test procedure, a throat swab specimen is collected, placed into a mixture of Reagents A and B, and extracted for 12 minutes. The extract flows to the Sample Well and is allowed to soak in. If group A streptococci are present in the specimen, they will react with anti-Strep A indicator antibody coupled to dye particles, migrate through the membrane as antigen-antibody-dye complexes, bind to the immobilized anti-Strep A antibody on the membrane, and generate a colored line in the Test position. The rest of the sample and unbound/bound dye complexes continue to migrate to the Control position where antibody to the anti-Strep A indicator antibody is immobilized. At this line, anti-Strep A indicator antibody unbound/ bound dye complexes form a Control line. Presence of two colored lines, one in the Test position and the other in the Control position, indicates a positive result, while the absence of a line in the Test position indicates a negative result.

The control line provides an additional quality control since it will only appear if:

• The anti-strep A antibody on the colloidal gold is active;
• The proper amount of reagent is added to the extraction well; and
• The wicking chemistry is working properly.

In the absence of the Control Line, the test should be considered invalid and should be repeated with a new device and a new swab sample.