INTENDED USE

The Leptospira Antibody Rapid Test kit is a lateral flow immunoassay for the simultaneous detection antibody to Leptospira interrogans (L. interrogans) 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 L. interrogans. Any reactive specimen with the Leptospira Antibody Rapid Test kit must be confirmed with alternative testing method(s).

SUMMARY AND EXPLANATION THE TEST

Leptospirosis occurs worldwide and is a common mild to severe health problem for humans and animals, particularly in areas with a hot and humid climate. The natural reservoirs for leptospirosis are rodents as well as a large variety of domesticated mammals. Human infection is caused by L. interrogans, the pathogenic member of the genus of Leptospira. The infection is spread via urine from the host animal.

After infection, leptospires are present in the blood until they are cleared after 4 to 7 days following the production of anti-L. interrogans antibodies, initially of the IgM class.

Culture of the blood, urine and cerebrospinal fluid is an effective means of confirming the diagnosis during 1st to 2nd weeks after exposure. Serological detection of anti-L. interrogans antibodies is also a common diagnostic method. Tests are available under this category: 1) The microscopic agglutination test (MAT); 2) ELISA; 3) Indirect fluorescent antibody tests (IFATs). However, all above mentioned methods require a sophisticated facility and well-trained technicians.

The Leptospira antibody is a simple serological test that utilizes antigens from L. interrogans and detects antibodies to these microorganisms simultaneously. The test can be performed by untrained or minimally skilled personnel, without cumbersome laboratory equipment and the result is available within 15 minutes.

PRINCIPLE

The Leptospira Antibody Rapid Test is a lateral flow chromatographic immunoassay.

The test cassette consists of: 1) a burgundy colored conjugate pad containing recombinant Leptospira specific antigen conjugated with colloid gold (Leptospira conjugates) and rabbit IgG-gold conjugates, 2) a nitrocellulose membrane strip containing a test band (T band) and a control band (C band). The T band is pre-coated with un-conjugated Leptospira antigen, and the C band is pre-coated with goat anti-rabbit IgG antibody.

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-Leptospira Ab if present in the specimen will bind to the Leptospira conjugates. The immunocomplex is then captured on the membrane by the pre-coated antigen, forming a burgundy colored T band, indicating a Leptospira Ab positive test result.

Absence of the T band 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 the T band. Otherwise, the test result is invalid and the specimen must be retested with another device.