For in vitro diagnostic use. The RIDASCREEN® Leishmania IgG Test is an enzyme immunoassay for the quantitative determination of specific IgG antibodies against Leishmania infantum in human serum. The test should be used for confirmation purposes when there is a suspected case of Leishmaniasis.
Leishmania is in the tropics and subtropics including the Mediterranean region a worldwide distributed parasite. Infection takes place by the bite of sand flies. Three clinical forms of leishmaniasis are known caused by different Leishmania species.
- Visceral leishmaniasis (kala-azar): The parasites reproduce in the reticuloendothelial (RE) cells of the spleen, liver, lymph nodes, bone marrow, intestinal mucosa and other organs. Untreated disease usually progresses to a fatal termination within 2 years, although fulminating infections may cause death within few weeks.
- Mucocutaneous leishmaniasis: The clinical appearance and histopathology of mucocutaneous leishmaniasis are identical to cutaneous leishmaniasis, except that it may produce later mucous membrane involvement. The mucosal lesions are painful and can cause great deformity with erosion of the nasal septum, palate, or larynx.
- Cutaneous leishmaniasis: In humans the disease is limited to the cutaneous tissues and causes an ulcerous papulation. It is the least severe form of the disease.
Beside direct parasite detection, antibody detection by ELISA is a suited diagnostic method especially in cases of visceral leishmaniasis. Antibodies can be detected in nearly all patients with visceral leishmaniasis. Furthermore therapy success can be controlled by decreasing antibody titers. In case of mucocutaneous leishmaniasis only up to 85 % of infected people show detectable antibodies. Antibodies are rarely detectable with cutaneous leishmaniasis. IgG antibodies are detected by use of a monovalent conjugate. Due to this, test sensitivity becomes higher especially at the beginning of antibody formation.
Purified antigens are coated to a microwell plate. Antibodies in the patient samples bind to the antigens and are determined during the second step by using enzyme-labelled Protein A (the conjugate). The enzyme converts the colourless substrate (H2O2/TMB) to a blue end product. The enzyme reaction is stopped by adding sulphuric acid and the colour of the mixture switches from blue to yellow at the same time. The final measurement is carried out at 450 nm on a photometer using a reference wavelength ≥ 620 nm.
|Test format||Microtiter plate with 96 wells (12 strips with 8 wells each; strips can be divided into single wells)|
|Incubation time||3 x 15 min at room temperature|