EVALUATION OF AN IMMUNORADIOMETRIC ASSAY FOR THYROTROPIN IN SERUM ANDPLASMA SAMPLES OF DOGS WITH PRIMARY HYPOTHYROIDISM

A commercially available immunoradiometric assay was used to measure t he thyrotropin (TSH; thyroid-stimulating hormone) concentration in the serum and plasma of 23 dogs. The basal concentration in five dogs wit h histologically confirmed primary hypothyroidism (median 0.18 mu g/l, range 0.16-0.72 mu g/l) was slightly, but not significantly, higher t han that in 13 clinically healthy dogs (median 0.09 mu g/l, range 0.06 -0.34 mu g/l). The TSH values in 11 euthyroid dogs with various dermat ological diseases (median 0.09 mu g/l, range 0.05-0.53 mu g/l) were si gnificantly lower than in the hypothyroid dogs, but there was consider able overlap. The assay alone was therefore not capable of giving a fi rm diagnosis. (C) 1996 W.B. Saunders Company Limited