The Leptospira IgG/IgM Cassette Rapid Test is a lateral flow chromatographic immunoassay. The test cassette consists of: 1) a burgundy colored conjugate pad containing recombinant L. interrogans antigens conjugated with colloidal gold (Leptospira conjugates) and rabbit IgG-gold conjugates, and A nitrocellulose membrane strip containing two test lines (M and G lines) and a control line (C line).
The M line is pre-coated with monoclonal anti-human IgM for the detection of anti-L. interrogans IgM, G line is pre-coated with reagents for the detection of anti-L. interrogans IgG, and the C line is pre-coated with goat anti rabbit IgG.
When an adequate volume of test specimen is dispensed into the sample well of the cassette, the specimen migrates by capillary action across the cassette. IgM anti-L. interrogans, if present in the specimen, will bind to the Leptospira conjugates.
The immunocomplex is then captured on the membrane by the pre-coated anti-human IgM antibody forming a burgundy colored M line, indicating a L. interrogans IgM positive test result. IgG anti-L. interrogans, if present in the specimen, will bind to the Leptospira conjugates. The immunocomplex is then captured on the membrane by the pre-coated reagents forming a burgundy colored G line, indicating a L. interrogans IgG positive test result.
Absence of any test lines (M and G) suggests a negative result. The test contains an internal control (C line) which should exhibit a burgundy colored line of the immunocomplex of goat anti-rabbit IgG/rabbit IgG-gold conjugates regardless of color development on any of the test lines. If the C line does not develop, the test result is invalid and the specimen must be retested with another device.