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Measurement of serum total thyroxine, triiodothyronine, free thyroxine, and thyrotropin concentrations for diagnosis of hypothyroidism in dogs.
J Am Vet Med Assoc. 1997 Dec 01; 211(11):1396-402.JA

Abstract

OBJECTIVE

To determine whether measurement of baseline serum concentrations of total thyroxine (T4), and triiodothyronine (T3), free T4, and thyrotropin (thyroid-stimulating hormone; TSH) would aid in the diagnosis of hypothyroidism in dogs.

DESIGN

Prospective case series.

ANIMALS

54 dogs with hypothyroidism, 54 euthyroid dogs with nonthyroidal disease initially suspected to have hypothyroidism, and 150 clinically normal dogs.

PROCEDURE

In the 54 dogs with hypothyroidism, diagnosis was established on the basis of clinical signs, results of routine laboratory and TSH stimulation tests, exclusion of concurrent nonthyroidal disease, and a good clinical response to treatment with L-thyroxine. Blood samples were collected from all dogs and were tested for thyroid hormone and TSH concentrations. Reference ranges for hormone concentrations were established on the basis of results for the 150 clinically normal dogs.

RESULTS

Of the 54 hypothyroid dogs, 48 (89%) had low total T4 concentrations, 3 had low-normal concentrations, and 3 had high concentrations because of T4 autoantibodies. In contrast, only 10 (18%) euthyroid dogs had low total T4 concentrations. Only 3 of 31 (10%) hypothyroid dogs had low T3 concentrations; 23 had concentrations within the reference range, and 5 had high concentrations because of T3 autoantibodies. Only 3 of 38 euthyroid dogs had low T3 concentrations. Of the hypothyroid dogs, 53 (98%) had low free T4 concentrations and 1 had a low-normal concentration. Only 4 (7%) euthyroid dogs had low free T4 concentrations. Of the hypothyroid dogs, 41 (76%) had high TSH concentrations, and 13 had TSH concentrations within the reference range. Of the euthyroid dogs, only 4 (8%) had high TSH concentrations. Of all single hormone measurements evaluated, measurement of free T4 concentration had the highest sensitivity (0.98), specificity (0.93), and accuracy (0.95) as a test for hypothyroidism; measurement of total T4 concentration had a lower sensitivity (0.89), specificity (0.82), and accuracy (0.85). Compared with measurement of total or free T4 concentration, measurement of TSH concentration had a lower sensitivity (0.76) and accuracy (0.84) but specificity (0.93) equal to that for measurement of free T4 concentration. When T4 (total or free) and TSH concentrations were evaluated together, specificity was higher than when T4 or TSH concentration was evaluated alone. Only 1 euthyroid dog had low T4 (total and free) and high TSH concentrations.

CLINICAL IMPLICATIONS

Results indicate that measurement of serum free T4 and TSH concentrations is useful for diagnosis of hypothyroidism in dogs. About a quarter of the dogs with confirmed hypothyroidism, however, will have serum TSH concentrations within reference limits.

Authors+Show Affiliations

Department of Medicine, Animal Medical Center, New York, NY 10021, USA.No affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article

Language

eng

PubMed ID

9394888

Citation

Peterson, M E., et al. "Measurement of Serum Total Thyroxine, Triiodothyronine, Free Thyroxine, and Thyrotropin Concentrations for Diagnosis of Hypothyroidism in Dogs." Journal of the American Veterinary Medical Association, vol. 211, no. 11, 1997, pp. 1396-402.
Peterson ME, Melián C, Nichols R. Measurement of serum total thyroxine, triiodothyronine, free thyroxine, and thyrotropin concentrations for diagnosis of hypothyroidism in dogs. J Am Vet Med Assoc. 1997;211(11):1396-402.
Peterson, M. E., Melián, C., & Nichols, R. (1997). Measurement of serum total thyroxine, triiodothyronine, free thyroxine, and thyrotropin concentrations for diagnosis of hypothyroidism in dogs. Journal of the American Veterinary Medical Association, 211(11), 1396-402.
Peterson ME, Melián C, Nichols R. Measurement of Serum Total Thyroxine, Triiodothyronine, Free Thyroxine, and Thyrotropin Concentrations for Diagnosis of Hypothyroidism in Dogs. J Am Vet Med Assoc. 1997 Dec 1;211(11):1396-402. PubMed PMID: 9394888.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Measurement of serum total thyroxine, triiodothyronine, free thyroxine, and thyrotropin concentrations for diagnosis of hypothyroidism in dogs. AU - Peterson,M E, AU - Melián,C, AU - Nichols,R, PY - 1997/12/12/pubmed PY - 1997/12/12/medline PY - 1997/12/12/entrez SP - 1396 EP - 402 JF - Journal of the American Veterinary Medical Association JO - J. Am. Vet. Med. Assoc. VL - 211 IS - 11 N2 - OBJECTIVE: To determine whether measurement of baseline serum concentrations of total thyroxine (T4), and triiodothyronine (T3), free T4, and thyrotropin (thyroid-stimulating hormone; TSH) would aid in the diagnosis of hypothyroidism in dogs. DESIGN: Prospective case series. ANIMALS: 54 dogs with hypothyroidism, 54 euthyroid dogs with nonthyroidal disease initially suspected to have hypothyroidism, and 150 clinically normal dogs. PROCEDURE: In the 54 dogs with hypothyroidism, diagnosis was established on the basis of clinical signs, results of routine laboratory and TSH stimulation tests, exclusion of concurrent nonthyroidal disease, and a good clinical response to treatment with L-thyroxine. Blood samples were collected from all dogs and were tested for thyroid hormone and TSH concentrations. Reference ranges for hormone concentrations were established on the basis of results for the 150 clinically normal dogs. RESULTS: Of the 54 hypothyroid dogs, 48 (89%) had low total T4 concentrations, 3 had low-normal concentrations, and 3 had high concentrations because of T4 autoantibodies. In contrast, only 10 (18%) euthyroid dogs had low total T4 concentrations. Only 3 of 31 (10%) hypothyroid dogs had low T3 concentrations; 23 had concentrations within the reference range, and 5 had high concentrations because of T3 autoantibodies. Only 3 of 38 euthyroid dogs had low T3 concentrations. Of the hypothyroid dogs, 53 (98%) had low free T4 concentrations and 1 had a low-normal concentration. Only 4 (7%) euthyroid dogs had low free T4 concentrations. Of the hypothyroid dogs, 41 (76%) had high TSH concentrations, and 13 had TSH concentrations within the reference range. Of the euthyroid dogs, only 4 (8%) had high TSH concentrations. Of all single hormone measurements evaluated, measurement of free T4 concentration had the highest sensitivity (0.98), specificity (0.93), and accuracy (0.95) as a test for hypothyroidism; measurement of total T4 concentration had a lower sensitivity (0.89), specificity (0.82), and accuracy (0.85). Compared with measurement of total or free T4 concentration, measurement of TSH concentration had a lower sensitivity (0.76) and accuracy (0.84) but specificity (0.93) equal to that for measurement of free T4 concentration. When T4 (total or free) and TSH concentrations were evaluated together, specificity was higher than when T4 or TSH concentration was evaluated alone. Only 1 euthyroid dog had low T4 (total and free) and high TSH concentrations. CLINICAL IMPLICATIONS: Results indicate that measurement of serum free T4 and TSH concentrations is useful for diagnosis of hypothyroidism in dogs. About a quarter of the dogs with confirmed hypothyroidism, however, will have serum TSH concentrations within reference limits. SN - 0003-1488 UR - https://www.unboundmedicine.com/medline/citation/9394888/Measurement_of_serum_total_thyroxine_triiodothyronine_free_thyroxine_and_thyrotropin_concentrations_for_diagnosis_of_hypothyroidism_in_dogs_ L2 - https://medlineplus.gov/hypothyroidism.html DB - PRIME DP - Unbound Medicine ER -