REF: DS177707 96 tests
The measured anti‐Tg value of a patient's sample can vary depending on the testing procedure used. The laboratory finding must therefore always contain a statement on the anti‐Tg assay method used. Anti‐Tg values determined on patient samples by different testing procedures cannot be directly compared with one another and could be the cause of erroneous medical interpretations.
If there is a change in the anti‐Tg assay procedure used while monitoring therapy, then the anti‐Tg values obtained upon changing over to the new procedure must be confirmed by parallel measurements with both methods.
Immunoassay for the in vitro quantitative determination of antibodies to thyroglobulin in human serum. The anti‐Tg determination is used as an aid in the detection of autoimmune thyroid diseases.
Summary (1, 2, 3, 4, 5, 6)
Thyroglobulin (Tg) is produced in the thyroid gland and is a main component in the lumen of the thyroid follicle. In synergy with the enzyme thyroid‐specific peroxidase (TPO), Tg has an essential function in the iodination of L‐tyrosine and in the formation of the thyroid hormones T4 and T3. Both Tg and TPO are potentially autoantigenic.
Elevated serum concentrations of antibodies against Tg (Tg‐autoantibodies) are found in subjects with autoimmunity‐based thyroiditis. High concentrations of anti‐Tg together with anti‐TPO are indicative ofchronic lymphocytic‐infiltrative thyroiditis (Hashimoto's disease). The frequency of thyroglobulin antibodies is approximately 70‐80 % in subjects with autoimmune‐thyroiditis, including Hashimoto's disease, and approximately 30 % in individuals with Graves' disease.The anti‐Tg assay is important for use in monitoring the course of Hashimoto's thyroiditis and for the differential diagnosis (cases of suspected autoimmune thyroiditis of unknown origin with negative anti‐TPO test results, Graves' disease without lymphocytic infiltration, and to rule out interference by Tg‐autoantibodies in the Tg test).
Although the sensitivity of the procedure can be increased by simultaneously determining additional thyroid antibodies (anti‐TPO, TSH‐receptor‐antibodies), a negative result does not definitively rule out the presence of an autoimmune disease. The level of the antibody titer does not correlate with the clinical activity of the disease. Titers that are elevated initially can become negative if the disease persists for a longer period of time or if remission occurs. If antibodies reappear after remission, a relapse is likely.
The Enzyme linked immunosorbent assays uses human antigen and rabbit antihuman IgG antibodies (anti-IgG).
• Coated Microplate, 8 x 12 strips, 96 wells. Pre-coated with human TG antigen.
• Calibrators, 6 vials, 1 mL each, ready to use; Concentrations: 0(A), 50(B) ,150(C), 500(D), 1000(E) and 2000(F) IU/mL.
• Enzyme Conjugate, 1 vial, 11.0 mL of HRP (horseradish peroxidase) labeled rabbit anti-human IgG antibodies (anti-IgG) in Tris-NaCl buffer containing BSA (bovine serum albumin). Contains 0.1% ProClin300 preservative.
• Serum Diluent: 1 vial, 11mL. Containing buffer salts and a dye
• Wash Solution Concentrate, 1 vial, 25 ml (40X concentrated), PBS-Tween wash solution.
• Substrate, 1 vial, 11ml, ready to use, (tetramethylbenzidine) TMB.
• Stop Solution, 1 vial, 6.0 ml of 1 mol/l sulfuric acid.
• IFU, 1 copy.
• Plate Lid: 2 pieces.
Materials required (but not provided)
• Microplate reader with 450nm and 620nm wavelength absorbent capability.
• Microplate washer.
• Plate shaker.
• Micropipettes and multichannel micropipettes delivering 50μl with a precision of better than 1.5%.
• Absorbent paper.
• Distilled water