INTENDED USE

The Chagas IgG/IgM Rapid Test is a lateral flow chromatographic immunoassay for the qualitative detection of Chagas virus IgG/IgM antibody in human serum ,plasma or whole blood. It is intended to be used as a screening test and as an aid in the diagnosis of infection with Chagas viruses. Any reactive specimen with the Chagas IgG/IgM Rapid Test must be confirmed with alternative testing method(s) and clinical findings.

SUMMARY AND EXPLANATION THE TEST

Chagas disease is an insect-borne, zoonotic infection by the protozoan T. cruzi, which causes a systemic infection of humans with acute manifestations and long term sequelae. It is estimated that 16-18 million individuals are infected worldwide, and roughly 50,000 people die each year from chronic Chagas disease (World Health Organization). Buffy coat examination and xenodiagnosis used to be the most commonly methods in the diagnosis of acute T. cruzi infection. However, both methods are either time consuming or lack of sensitivity. Recently, serological test becomes the mainstay in the diagnosis of Chagas’s disease. In particularly, recombinant antigen based tests eliminate false-positive reactions which are commonly seen in the native antigen tests. The Chagas Ab Combo Rapid Test is an instant antibody test which detects IgG antibodies the T. cruzi within 15 minutes without any instrument requirements. By utilizing T. cruzi specific recombinant antigen, the test is highly sensitive and specific.

PRINCIPLE

The Chagas IgG/IgM Rapid Test is a lateral flow chromatographic immunoassay. The test cassette consists of: 1) a burgundy colored conjugate pad containing Chagas recombinant envelope antigens conjugated with colloid gold (dengue conjugates) and rabbit IgG-gold conjugates,2) a nitrocellulose membrane strip containing two test bands (G and M bands) and a control band (C band). The G band is pre-coated with the antibody for the detection of IgG anti-Chagas virus, M band is coated with antibody for the detection of IgM anti-Chagas virus, 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. IgG anti-Chagas virus if present in the specimen will bind to the Chagas conjugates. The immunocomplex is then captured by the reagent coated on the G band, forming a burgundy colored G band, indicating a Chagas virus IgG positive test result and suggesting a recent or repeat infection. IgM anti-Chagas virus, if present in the specimen, will bind to the Chagas conjugates. The immunocomplex is then captured by the reagent pre-coated on the M band, forming a burgundy colored M band, indicating a Chagas virus IgM positive test result and suggesting a fresh infection. Absence of any test bands (G and M) 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.