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Anti-Thyroid Peroxidase
REF: DS177708 96 tests 

Intended use
Immunoassay for the in vitro quantitative determination of antibodies to thyroid peroxidase in human serum. The anti‐TPO determination is used as an aid in the 
diagnosis of autoimmune thyroid diseases.

Summary (1, 2, 3, 4, 5, 6)
Thyroid‐specific peroxidase (TPO) is present on the microsomes of thyrocytes and is expressed at its apical cell surface. In synergy with thyroglobulin (Tg) this enzyme has an essential function in the iodination of L‐tyrosine and the chemical coupling of the resulting mono‐ and di‐iodotyrosine to form the thyroid hormones T4, T3, and rT3.TPO is a potential autoantigen. Elevated serum titers of antibodies to TPO are found in several forms of thyroiditis caused by autoimmunity. The still frequently found term “microsomal antibody” originates from the time when TPO had not yet been identified as an antigen in autoimmunity caused by microsomes. In the 
clinical sense the two terms anti‐TPO and microsomal antibody can be used synonymously; there are differences, however, with regard to the test methods.
High anti‐TPO titers are found in up to 90 % of patients with chronic Hashimoto's thyroiditis. In Graves' disease, 70 % of the patients have an elevated titer. 
Although the sensitivity of the procedure can be increased by simultaneously determining other thyroid antibodies (anti‐Tg, TSH‐receptor‐antibody - TRAb), a negative finding does not rule out the possibility of an autoimmune disease. The magnitude of the antibody titer does not correlate with the clinical activity of the disease. Initially elevated titers can become negative after lengthy periods of illness or during remission. If antibodies reappear following remission, then a relapse is probable.
Whereas the usual microsomal antibody tests employ unpurified microsomes as an antigen preparation, the anti‐TPO tests use a purified peroxidase. The two procedures are of comparable performance in terms of clinical sensitivity, but better lot‐to‐lot consistency and higher clinical specificity can be expected from anti‐TPO tests due to the higher quality of the antigen used.The Enzyme linked immunosorbent assays uses human antigen and rabbit antihuman IgG antibodies (anti-IgG).

Materials provided

• Coated Microplate, 8 x 12 strips, 96 wells. Pre-coated with human TPO antigen.
• Calibrators, 6 vials, 1 mL each, ready to use; Concentrations: 0(A), 25(B) ,50(C), 100(D), 250(E) and 500(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. 
• Incubator.
• Plate shaker.
• Micropipettes and multichannel micropipettes delivering 50μl with a precision of better than 1.5%.
• Absorbent paper.
• Distilled water