RIDASCREEN^® Toxocara IgG

Product Code. K7421

Intended use:

For in vitro diagnostic use. The RIDASCREEN^® Toxocara IgG test is an enzyme immunoassay (EIA) for the qualitative determination of IgG antibodies against Toxocara canis in human serum. The test should be used for confirmation purposes when there is a suspected case of toxocariasis or for clarifying the immune status.

 General information:

Toxocariasis is an infection caused by migration of roundworm Toxocara larvae to organs and tissues. Infected cats or dogs excrete eggs with their feces. Humans are infected by ingestion of eggs from the environment (studies of United Kingdom’s parks showed 24 % of soil samples with eggs) or by direct contact to infected animals. After their ingestion, eggs free in the gut the larvae, which go across gut’s walls and migrate to different organs (liver, lungs, CNS, eyes, muscles) through the circulatory system. Incubation period may range from weeks to months, depending on infection intensity and patient sensibility. Distribution is probably world wide. In United States and United Kingdom the disease has been target of greater attention, but there is probably not less prevalence in other countries. The grave form occurs sporadically, affecting rather children from 14 to 40 months old, though occurs even to older children. Few times, adults are infected. That lower incidence in adults and older children is rather related with a less exposition to the disease.
The demonstration of the Toxocara larvae by means of liver biopsy confirms the clinical diagnosis, but it is rarely justified. Antibody detection by ELISA enables a fast diagnosis. But the diagnosis is complicated by the fact that the antibody response varies widely depending on worm burden and location.

Test principle
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.

Specifications: