Expected use
The Filariasis IgG / IgM Combo Rapid Test is a lateral flow immunoassay for the simultaneous detection and differentiation of IgG and IgM anti-lymphatic filarial parasites (W. Bancrofti and B. Malayi) in human serum or plasma. 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 specimen reactive with the IgG / IgM Rapid Combination Filariasis Test should be confirmed by alternative test methods.
Summary and explanation
Lymphatic filariasis known as elephantiasis, caused mainly by W. bancrofti and B. malayi, affects about 120 million people in 80 countries. The disease is transmitted to humans by the bites of infected mosquitoes into which microflaria sucked from an infected human subject develop into third instar larvae. Repeated and prolonged exposure to infected larvae is generally required for the establishment of human infection. The definitive parasitological diagnosis is the demonstration of microflaria in blood samples. However, this gold standard test is restricted by the requirement for nocturnal blood collection and a lack of adequate sensitivity.
Detection of circulating antigens is commercially available. Its usefulness is limited for W. bancrofti. Additionally, microfilaremia and antigenemia develop months to years after exposure. Antibody detection provides an early means of detecting infection with filarial parasites. The presence of IgM in the parasite antigens suggests a current infection, whereas IgG corresponds to a late stage of infection or a past infection. In addition, the identification of conserved antigens allows the "pan-filaria" test to be applied. The use of recombinant proteins eliminates cross-reaction with individuals suffering from other parasitic diseases. The combined rapid IgG / IgM filariasis test uses conserved recombinant antigens to simultaneously detect IgG and IgM for W. bancrofti and B. malayi parasites without restriction of sample collection.
