Canine Hypothyroidism: Prevalence of Positive TgAA in 7237 Laboratory Samples from Beagles
Nachreiner RF, Bowman M, Refsal KR, Graham PA, A Provencher Bolliger
Click on title for full text PDF
Prevalence of autoantibodies to thyroglobulin in dogs with nonthyroidal diseases
Nachreiner RF, Refsal KR, Graham PA, Hauptman J, Watson GL. Amer. J. Vet. Research, 1998; 59(8):951-955. Reprints of this article are available from Oxford Laboratories on request.
Summary: Samples from 146 dogs were used to determine the sensitivity and accuracy of the TgAA assay. It was found that this assay is highly sensitive and provides specific identification of lymphocytic autoimmune thyroiditis in dogs. This means that the TgAA assay is excellent as a test for early diagnosis in dogs who may not yet show symptoms, but who are ready to be used for breeding.
In another part of the study, 91 random-source dogs were tested and 3.3% were found to have positive TgAA, and 2.2% had clinical signs of hypothyroidism. These results indicate that primary hypothyroidism is not an uncommon problem in dogs.
Overall, the TgAA assay was found to be 96% accurate.
Thyroglobulin autoantibody measurement helps confirm thyroid status in dogs with discordant serum thyroxine and thyrotropin concentrations.
Dixon, R.M. and Mooney, C.T. This research, conducted at Glasgow University, was presented at an international meeting of veterinary endocrinologists in 1998.
Abstract: The measurement of total serum thyroxine (T4) and endogenous thyrotropin (eTSH) is routinely used to assist in the diagnosis of canine hypothyroidism. However, a significant number of discordant cases exist whereby T4 is normal and eTSH elevated or T4 depressed and eTSH normal and such cases are a considerable diagnostic problem. Thyroglobulin autoantibodies (TgAA) are produced in response to thyroid pathology including thyroiditis, a common cause of hypothyroidism. TgAA was measured using a commercially available assay (Canine thyroglobulin autoantibody immunoassay kit, Oxford Laboratories, Michigan) in serum from 121 dogs in which hypothyroidism was suspected. Each dog was classified as either euthyroid (n=77) or hypothyroid (n=44) based on the results of a bovine TSH response test. TgAA was positive in 16 (36%) and equivocal in 8 (18%) of the hypothyroid group, and negative in 72 (94%) and equivocal in 5 (6%) of the euthyroid group. No euthyroid dog was positive for TgAA. In discordant cases with subnormal basal T4 but normal eTSH concentrations, TgAA was equivocal in 1 (6%) and negative in 15 (94%) of 16 euthyroid dogs, and postive in 3 (43%), negative in 3 (43%), and equivocal in 1 (14%) of 7 hypothyroid dogs. In discordant dogs with normal basal T4 but elevated eTSH concentrations, TgAA was negative in 9 (90%) and equivocal in 1 (10%) of 10 euthyroid dogs, and negative in a solitary euthyroid dog. Measurement of TgAA was particularly helpful in the confirmation of hypothyroidism in those hypothyroid dogs with discordant basal T4 and eTSH results. The presence of TgAA in nearly half of the hypothyroid dogs with normal eTSH concentrations suggests central hypothyroidism is not the predominant cause of this abnormality. TgAA measurement is a useful test for hypothyroidism particularly in cases with discordant T4 and eTSH results. (reprinted with permission of the authors)
Etiopathologic Findings of Canine Hypothyroidism
PA Graham, KR Refsal, and RF Nachreiner
Veterinary Clinics of North America: Small Animal Practice 37-4: 617-631; 2007
Prevalence of serum thyroid hormone autoantibodies in dogs with clinical signs of hypothyroidism
RF Nachreiner, et al.
Journal of the American Veterinary Medical Association 220-4; 466-471; 2002
A Multi-Breed Genome-Wide Association Analysis for Canine Hypothyroidism Identifies a Shared Major Risk Locus on CFA12
M Bianchi, et al.
PLoS One 10-8; e0134720. Doi:10.1371/journal.pone.0134720; 2015
Prevalence of autoantibodies to thyroglobulin in dogs with nonthyroidal illness
RF Nachreiner, et al.
American Journal of Veterinary Research 59-8: 951-955, 1998
Association of canine hypothyroidism with a common major histocompatibility complex DLA class II allele
LJ Kennedy, et al.
Tissue Antigens 68-1: 82-86, 2006