ClinQuiz: LDDS - Answer 3C

3C-Correct. The cortisol concentration is 10 µg/dl at baseline, 4 µg/dl four hours after dexamethasone administration, and 10 µg/dl eight hours after dexamethasone administration, thus the dog exhibits at least 50% cortisol suppression at some point during the test, which is diagnostic for PDH. This inverted, or escape, pattern of suppression is the most common LDDS test result seen in the laboratory. The increase in cortisol concentrations between four and eight hours after dexamethasone administration reflects the accelerated dexamethasone metabolism that often occurs in dogs with hyperadrenocorticism.

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