2015 ACVIM Forum Research Abstract Program

Median serum concentrations of T4, T3, and FT4 in the 786 hyperthyroid cats (7.9 lg/dl, 151 ng/dl, 100 pmol/L, respectively) were significantly higher (P < 0.001, Kruskal-Wallis test) than median concentrations in the 28 euthyroid cats with suspected thyroid disease (2.2 lg/dl, 54 ng/dl, 38 pmol/L) or the 120 clinically normal cats (2.2 lg/dl, 50 ng/dl, 33 pmol/L). Of the hyperthyroid cats, 742 (94%), 513 (65%), and 757 (96%) had high serum concentrations of of T4, T3, and FT4, respectively; of the 28 euthyroid cats, 2 (7%,), 1 (3.5%), and 5 (18%) had falsely high values of T4, T3, or FT4, respectively. The calculated sensitivity of T4, T3, and FT4 as a diagnostic test for hyperthyroidism was 94%, 65%, and 96%, respectively, whereas the specificity of each test was 93%, 96%, and 82%, respectively.