Evaluation of a novel, sensitive thyroid-stimulating hormone assay as a diagnostic test for thyroid disease in cats

Am J Vet Res. 2024 Feb 23;85(5):ajvr.23.12.0278. doi: 10.2460/ajvr.23.12.0278. Print 2024 May 1.


Objective: Clinicians commonly use thyroid-stimulating hormone (TSH) concentrations to diagnose thyroid disorders in humans and dogs. In cats, canine TSH chemiluminescent immunoassays (CLIA) assays are commonly used to measure TSH, but these TSH-CLIAs cannot measure low TSH concentrations (< 0.03 ng/mL) and therefore cannot distinguish between low-normal concentrations and truly low TSH concentrations (characteristic of hyperthyroidism). Our aim was to evaluate a novel TSH assay based on bulk acoustic wave (BAW) technology that has lower functional sensitivity (0.008 ng/mL) than TSH-CLIAs.

Animals: 169 untreated hyperthyroid cats, 53 cats treated with radioiodine (131I), 12 cats with chronic kidney disease (CKD), and 78 clinically healthy cats.

Methods: Serum concentrations of T4, TSH-CLIA, and TSH-BAW were measured in all cats. Untreated hyperthyroid cats were divided into 4 severity groups (subclinical, mild, moderate, and severe), whereas 131I-treated cats were divided into euthyroid and hypothyroid groups.

Results: Test sensitivity, specificity, and positive predictive value for identifying hyperthyroidism were higher for TSH-BAW (90.5%, 98.9%, and 86.9%) than TSH-CLIA (79.9%, 76.7%, and 21.7%; P < .001). Test sensitivity for identifying 131I-induced hypothyroidism was only 45.5% for T4 versus 100.0% for both TSH-CLIA and TSH-BAW (P = .03), whereas TSH-BAW had a higher positive predictive value (100%) than did either TSH-CLIA (81.2%) or T4 (71.9%).

Clinical relevance: Serum TSH-BAW alone or together with T4 is a highly sensitive and specific diagnostic test for evaluating feline hyperthyroidism and iatrogenic hypothyroidism. Finding low serum TSH-BAW concentrations is most useful for diagnosing subclinical and mild hyperthyroidism, in which serum T4 remains within or only slightly above the reference interval.

Keywords: hyperthyroidism; hypothyroidism; thyrotrophin; thyrotropin; thyroxine.

Publication types

  • Evaluation Study

MeSH terms

  • Animals
  • Cat Diseases* / blood
  • Cat Diseases* / diagnosis
  • Cats
  • Female
  • Hyperthyroidism / blood
  • Hyperthyroidism / diagnosis
  • Hyperthyroidism / veterinary
  • Hypothyroidism / blood
  • Hypothyroidism / diagnosis
  • Hypothyroidism / veterinary
  • Immunoassay / veterinary
  • Iodine Radioisotopes
  • Male
  • Predictive Value of Tests
  • Sensitivity and Specificity*
  • Thyroid Diseases / blood
  • Thyroid Diseases / diagnosis
  • Thyroid Diseases / veterinary
  • Thyrotropin* / blood
  • Thyroxine / blood


  • Thyrotropin
  • Iodine Radioisotopes
  • Thyroxine