Filariasis IgG/IgM Test Kit (Colloidal Gold)

INTENDED USE

The Filariasis IgG/IgM Test Kit (Colloidal Gold) is a lateral flow immuno assay for the simultaneous detection and differentiation of IgG and IgM anti-lymphatic filarial parasites (W. Bancrofti and B. Malayi) in human serum, plasma or whole blood. This test is intended to be used as a screening test and as an aid in the diagnosis of infection with lymphatic filarial parasites. Any reactive specimen with the Filariasis IgG/IgM Test Kit (Colloidal Gold) must be confirmed with alternative testing methods. The diagnosis should be confirmed in combination with clinical symptoms or other conventional testing methods.

SUMMARY AND EXPLANATION
The lymphatic filariasis known as Elephantiasis, mainly caused by W. bancrofti and B. malayi, affects about 120 million people over 80 countries. The disease is transmitted to humans by the bites of infected mosquitoes within which the microflariae sucked from an infected human subject develops into third-stage larvae. Generally, repeated and prolonged exposure to infected larvae is required for establishment of human infection.
The definitive parasitologic diagnosis is the demonstration of microflariae in blood samples.However, this gold standard test is restricted by the requirement for nocturnal blood collection and lack of adequate sensitivity. Detection of circulating antigens is commercially available. Its usefulness is limited for W. bancrofti.In addition, microfilaremia and antigenemia develop from months to years after exposure.
Antibody detection provides an early means to detect filarial parasite infection. Presence of IgM to the parasite antigens suggest current infection, whereas, IgG corresponds to late stage of infection or past infection.Furthermore, identification of conserved antigens allows 'panfilaria' test to be applicable. Utilization of recombinant proteins eliminates cross-reaction with individuals having other parasitic diseases.The Filariasis IgG/IgM Rapid Test uses conserved recombinant antigens to simultaneously detect IgG and IgM to the W. bancrofti and B. malayiparasites without the restriction on specimen collection.

Test Principle

The Filariasis IgG/IgM Test Kit (Colloidal Gold) is a lateral flow chromatographic immunoassay. 

The test card contains:

1. Colloidal gold-labeled antigen and quality control antibody complex.

2. Nitrocellulose membranes immobilized with two test lines (M line and G line) and one quality control line (C line).

When an appropriate amount of sample is added to the sample well of the test card, the sample will move forward along the test card under capillary action.

W. bancrofti or B. malayi IgM antibodies if present in the specimen willbind to the Filariasis 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 W. bancrofti or B. malayi IgM positive test result. 
W.bancrofti or B. malayi IgG antibodies if present in the specimen will bind to the Filariasis conjugates. The immunocomplex is then captured by the pre-coated reagents on the membrane, forming a burgundy colored G line, indicating a W. bancrofti or B. malayi 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  conjugate regardless of the color development on any of the test lines.Otherwise, the test result is invalid and the specimen must be retested with another device. 

Reagents And Materials Supplied

Interpretation Of The Result

NEGATIVE: If only the quality control line C appears, and the test lines M and G are not purple/red, it indicates that no antibody is detected, and the result is negative.

POSITIVE:  IgM positive: If both the quality control line C and the test line M appear purple/red, it indicates that the Ig M antibody is detected, and the result is positive for Ig M antibody.

IgG positive: If both the quality control line C and the test line G appear purple/red, it indicates that the Ig G antibody is detected, and the result is positive for Ig G antibody.

IgM and IgG positive: If the quality control line C and the test lines M and G all appear purple/red, it indicates that the Ig M and Ig G antibodies are detected, and the result is positive for both IgM and IgG antibodies.

INVALID:  If the quality control line C is not displayed, the test result is invalid regardless of whether there is a purple/red test line, and it should be tested again.