Diagnosis of canine hyperadrenocorticism.

Diagnosis of canine hyperadrenocorticism can only be made when a suspicion of the disorder persists after completion of a thorough history and physical examination. The first diagnostic testing steps include a complete blood count, serum biochemical tests, and urinalysis with urine culture. Radiography or ultrasonography may also be necessary, depending on physical findings. Screening tests are next applied to support or exclude the clinical diagnosis of hyperadrenocorticism. After the diagnosis has been made, discrimination tests are applied to determine whether the cause is pituitary or adrenal. The limitations of screening tests, particularly in the presence of nonadrenal diseases, cannot be overemphasized. We recommend that neither screening tests nor discrimination tests for hyperadrenocorticism be used in dogs with concurrent nonadrenal disease.