The Candida albicans IgM, IgA and IgG tests are rapid ELISA methods for the detection of IgM, IgA or IgG antibodies to Candida albicans. They are intended for the diagnosis of Candida albicans infection. The components of the tests are for in vitro diagnostic use only.
A number of fungal pathogens can spread systemically from the intestinal lumen to the visceral organs. Although hundreds of Candida species are known, C. albicans and C. tropicalis cause over 80% of Candida infections in man. Candida probably enters the newborn in the first days of life and is a normal inhabitant of the gut. Systemic candidiasis is a fungal infection of the deep organs resulting from the overgrowth and spread of Candida. It is a significant cause of death in immuno-compromised patients or those undergoing prolonged antibiotic therapy. Candida infection is not routinely tested for in blood donors and may also be transmitted via blood transfusions. Elevated Candida IgG levels are also frequently encountered in elderly patients (>60 years).
Recent infection with systemic candidiasis is characterised by elevated IgM, IgA and IgG titres.
Principle of the ELISA Candida test
Diluted serum samples are incubated with C. albicans antigens immobilised on microtitre wells. After washing away unbound serum components, rabbit anti-human IgA, IgM or IgG conjugated to horseradish peroxidase is added to the wells, and this binds to surface-bound antibodies in the second incubation. Unbound conjugate is removed by washing, and a solution containing 3,3 tetramethylbenzidine (TMB) and enzyme substrate is added to trace specific antibody binding. Addition of stop solution terminates the reaction and provides the appropriate pH for colour development. The optical densities of the standards, positive control and samples are measured using a microplate reader at 450nm. Optical density is directly proportional to antibody activity in the sample.
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