Typhoid IgG/IgM Rapid Test Cassette is a lateral flow chromatographic immunoassay. The test cassette consists of: 1) a burgundy colored conjugate pad containing recombinant S. typhoid H antigen and O antigen conjugated with colloid gold (Typhoid conjugates) and rabbit IgG-gold conjugates, 2) a nitrocellulose membrane strip containing two test bands (T1 and T2 bands) and a control band (C band). The T1 band is pre-coated with monoclonal anti-human IgM for the detection of IgM anti-S. typhi, T2 band is pre-coated with reagents for the detection of IgG anti-S. typhi, and the C band is pre-coated with goat anti rabbit IgG.
When an adequate volume of test specimen is dispensed into the sample well of the test cassette, the specimen migrates by capillary action across the cassette. Anti-S. typhi IgM if present in the specimen will bind to the Typhoid conjugates. The immunocomplex is then captured on the membrane by the precoated anti-human IgM antibody, forming a burgundy colored T1 band, indicating a S. typhi IgM positive test result.
Anti-S. typhi IgG if present in the specimen will bind to the Typhoid conjugates. The immunocomplex is then captured by the pre-coated reagents on the membrane,forming a burgundy colored T2 band, indicating a S. typhi IgG positive test result.
Absence of any T bands (T1 and T2) suggests a negative result.The test contains an internal control (C band) which should exhibit a burgundy colored band of the immunocomplex of goat anti rabbit IgG/rabbit IgG-gold conjugate regardless of the color development on any of the T bands.Otherwise,the test result is invalid and the specimen must be retested with another device.