Testing for hypothyroiditis and TgAA
Thyroglobulin (Tg) is a 660 kD thyroid protein that occurs as a 19S dimer. During synthesis, both monomers appear to be identical, but are heterogeneous following glycosylation and iodination. Tg is the major storage form for thyroxine and triiodothyronine in the thyroid follicle. Tg has many epitopes, as anticipated for a protein of its size. Monoclonal antibodies with multiple specificities have been developed against human Tg, and the reactivity of some may be inhibited by T4 but not by other iodoamino acids. Several studies suggest the presence of autoantibodies (AA) to Tg in dogs to be an indicator of lymphocytic thyroiditis. This disease is comparable, histologically, to Hashimoto's thyroiditis in human beings. Evidence suggests that autoimmune thyroiditis is due to a genetic defect in humans and dogs.

This indirect enzyme immunoassay is for the determination of Tg autoantibodies in canine serum. Purified canine Tg is coated on the wells of a 96-well polystyrene plate. Canine test sera, along with positive and negative canine control sera are added to the plate and allowed to bind. Enzyme labeled anti-immunoglobulin is then added and autoantibodies are allowed to incubate and bind. Enzyme substrate is then added and the plate is incubated. The higher the concentration of TgAA in the serum sample, the higher amount of substrate bound and the brighter the color. The reaction is terminated by the addition of stop solution.

Canine autoimmune thyroiditis can be detected by TgAA ELISA. Oxford Laboratories has several products available for veterinarians and vet labs to use for the detection of autoimmune thyroiditis. Additionally, there are a number of veterinary labs that test for canine autoimmune thyroiditis. View Veterinary Laboratories.

VT 10 Canine Thyroglobulin Autoantibody Immunoassay
This assay kit is primarily used by veterinary labs for testing up to 42 samples in duplicate. Dogs that are to be registered with OFA should have this test performed by a certified testing lab. We recommend that the VT 10 and VT 11 kits be used together by labs that process large numbers of samples.

VT 11 Canine Non-Specific Binding Assay
All ELISAs are subject to non-specific binding (NSB) due to interfering factors in serum. Up to 10% of positive results can be or are false positives. For the most accurate results when using the VT 10 assay kit, we recommend incorporating the Non-Specific Binding assay kit to reduce the number of false positive and inconclusive results.

VT 12 Canine Thyroglobulin Autoantibody Immunoassay with Non-Specific Binding
This kit is a combination of the VT 10 and the VT 11 assays. Each plate has alternating rows for TgAA and NSB. This kit can be used by labs that test fewer samples.