3102 – Medizym® anti-Tg

The Medizym® anti-Tg is a quantitative immunoassay for the determination of IgG antibodies against thyroglobulin (Tg) in human serum. The Medizym® anti-Tg is intended as an aid in the diagnosis of autoimmune thyroid diseases in conjunction with other clinical and laboratory findings.

Thyroglobulin (Tg), an iodine containing glycoprotein and precursor of the thyroid hormones thyroxine (T4) and triiodothyronine (T3), makes up a major part of thyroid colloid. The biosynthesis of Tg is regulated by thyrotropin, the only thyroid tissue that can produce, store and secrete Tg; Tg is thus organ- and tissue specific. This specificity is the main indication of the Tg determination in monitoring differentiated thyroid carcinoma, essential in the early detection and exclusion of metastases or tumour relapses. This indication is also used in the follow-up of radioiodine treatments. Serum Tg measurements plays a major diagnostic role in chronic autoimmune thyroiditis and for the differential diagnosis of hypothyroidism including the subclinical or latent type. The anti-Tg determination is also valuable in Graves’ disease, particularly if the TSH receptor antibody value is negative, but the disease is clinically suspected. Increased Tg values relative to the reference range in healthy individuals are also observed in benign thyroid diseases. Other indications of increased serum Tg levels are found in various non-malignant thyroid diseases, e.g. Hashimoto`s thyroiditis, Graves` disease, and non-toxic diffuse goiter.

The ELISA (Enzyme Linked Immunosorbent Assay) is an immunoassay for the determination of specific antibodies. The strips of the microtiter plate are coated with test-specific antigens. If antibodies are present in the patient´s sample, they bind to the antigens. A secondary antibody conjugated with the enzyme peroxidase detects the generated immune complex. A colorless substrate is converted into the colored product. The signal intensity of the reaction product is proportional to the antibody activity in the sample. After stopping the signal intensity of the reaction product is measured photometrically.

The immunoassay is designed for manual professional in vitro diagnostic use.