OFA Canine Thyroid RegistryRay Nachreiner, D.V.M., Ph.D.
Autoimmune thyroiditis (Hashimoto's Disease) is the most common cause of primary hypothyroidism in dogs. The disease has variable onset, but tends to clinically manifest itself at 2 to 5 years of age. Hence, dogs may be clinically normal for years, only to become hypothyroid at a later date. The markers for autoimmune thyroiditis, autoantibody formation (autoantibodies to thyroglobulin, T4 or T3), occur prior to the occurrence of clinical signs. The majority of dogs that develop autoantibodies have them by 3 to 4 years of age. Development of autoantibodies at any time in the dogs life is an indication that the dog, most likely, has the genetic form of the disease.
As a result of the variable onset of the presence of autoantibodies, periodic testing will be necessary. Dogs that are negative at 1 year of age may become positive at 6 years of age. Hence, dogs should be tested every year or two in order to be certain that they have not developed the condition. Since the majority of affected dogs will have autoantibodies by 4 years of age, annual testing for the first 4 years is recommended. After that, testing every other year should suffice. Unfortunately, a negative at any one time will not guarantee that the dog does not have Hashimoto's disease.
The registry data can be used by breeders in determining which dogs are best for their breeding program. Knowing the status of the dog and the status of the dog's lineage, breeders and genetic counselors can decide which matings are most appropriate for reducing the incidence of Hashimoto's disease in the offspring.
The method for classifying the thyroid status will be accomplished using state of the art assay methodology.
Indices of thyroiditis:
CERTIFICATION a. Normal FT4D 8-30pmoVL cTSH 7-40 mU/L TgAA Negative b. Positive advanced autoimmune thyroiditis FT4D <8pmol/L cTSH >40mU/L TgAA Positive c. Positive compensating autoimmune thyroiditis FT4D 8-30 pmoVL cTSH 10-100 mU/L TgAA Positive d. Positive idiopathic hypothyroidism FT4D <8pmoVL cTSH >40mU/L TgAA Negative
The laboratory certification process will include quality control, quality assurance and reagent certification.
Laboratories may apply and if successful will be approved to perform analyses for OFA thyroid certification. A site visit by a qualified veterinary endocrinologist chosen by OFA will be required and continued quality assurance and quality control will be necessary to maintain certification. Fully certified status can be obtained by passing the site visit and passing the results of the first OFA quality assurance assay result test.
The approved laboratory must be contacted for the appropriate submission forms, sample handling procedures and laboratory service fee before collecting the sample. Currently, samples may be submitted to:
Animal Health Diagnostic Laboratory B629 W. Fee Hall-B Michigan State University Lansing, MI 48824-1315 517-353-0621 Diagnostic Laboratory New York State College of Veterinary Medicine Cornell University, Upper Tower Rd Ithaca, NY 14851 607-253-3673 Animal Health Laboratory University of Guelph Bldg. 49, McIntosh lane Guelph, Ontario Canada N1G 2W1 519-824-4120 ext. 4518 Veterinary Diagnostic Laboratory Attn: Sample Handling College of Veterinary Medicine University of Minnesota 1333 Gortner Ave St. Paul, MN 55108 612-625-6782 University of California Veterinary Medical Teaching Hospital Clinical Pathology, Chemistry, Room 1017 1 Garrod Drive Davis, CA 95616 530-752-7380 Texas Veterinary Medical Diagnostic Laboratory 1 Sippel Rd College Station, TX 77843 409-845-3414Other laboratories will be approved at a later date.