Description:

The Diagnostic Automation Thyroglobulin Enzyme-Linked Immunosorbent Assay (ELISA) is intended for the detection and semi-quantitation of antibodies to thyroglobulin in human sera. The assay is to be used to detect antibodies in a single serum specimen. The results of the assay are to be used as an aid to the diagnosis of thyroid autoimmune disease. This kit is for in vitro diagnostic use.

Autoimmune thyroid disease is characterized by the presence of circulating autoantibody directed to thyroid antigens. Hashimoto and Graves diseases are the best known of these diseases. The majority can be diagnosed by clinical presentation and their antibody profiles to thyroglobulin and thyroid microsomes. Therefore, immunoassays for thyroid antibodies are useful for diagnostic evaluations of thyroid autoimmune disease. Thyroglobulin is a water soluble glycoprotein that is involved in the storage and synthesis of thyroid hormones. The thyroid microsomal antigen has been shown to be the enzyme thyroid peroxidase (TPO). Antibodies to thyroglobulin and or microsomal antigen are present in most patients with goitrous thyroiditis (Hashimoto disease), atrophic thyroiditis (myxedema) and about 70-90% of Gravesâ??s disease. Antibodies are also found in about half of the patients with primary hypothyroidism and thyrotoxicosis, and 10-20% of patients with simple goiters and thyroid tumors. There is also a relationship between thyroid antibodies and diabetes mellitus. Thyroid autoantibodies are present in about 6-7% of normal and their incidence increases with Ag. Classically, autoantibody to thyroid antigens are detected by precipitation reactions, hemagglutination and by immunoflourescence. However the tests are subjective and lack high sensitivity. Enzyme- Linked Immunosorbent Assays (ELISAs) combine greater sensitivity, objective reading and ease of use. ELISAs have been developed and validated for detecting autoantibody to thyroid antigens.

The DAI Thyroglobulin test is an Enzyme-Linked Immunosorbent Assay to detect IgG, IgA, and IgM antibodies consist of Thyroglobulin antigens. Purified Thyroglobulin antigens are attached to a solid phase microassay well. Enzyme-Linked Immunosorbent Assays (ELISA) relies on the ability of biological materials (i.e., antigens) to adsorb to plastic surfaces such as polystyrene (solid phase). When antigens bound to the solid phase are brought into contact with a patient's serum, antigen specific antibody, if present, will bind to the antigen on the solid phase forming antigen-antibody complexes. Excess antibody is removed by washing. This is followed by the addition of goat anti-human IgG, A, M conjugated with horseradish peroxidase which then binds to the antibody-antigen complexes. The excess conjugate is removed by washing, followed by the addition of Chromogen/Substrate, tetramethylbenzidine (TMB). If specific antibody to the antigen is present in the patient's serum, a blue color develops. When the enzymatic reaction is stopped with 1N H2SO4, the contents of the wells turn yellow. The color, which is indicative of the concentration of antibody in the serum, can be read on a suitable spectrophotometer or ELISA microwell plate reader.