Pitfalls in the interpretation of the cosyntropin stimulation test for the diagnosis of adrenal insufficiency.

PURPOSE OF REVIEW: Adrenal insufficiency is a rare disease characterized by cortisol deficiency. The evaluation of patients suspected of having adrenal insufficiency can be challenging because of the rarity of the disease and limitations in the biochemical assessment of the cortisol status by either basal or dynamic testing [adrenocorticotropic hormone (ACTH) stimulation test]. Prompt and adequate diagnosis is of paramount importance to avoid adverse outcomes. We aimed to summarize the recent developments in the conduction and interpretation of the ACTH stimulation test for the diagnosis of adrenal insufficiency.

RECENT FINDINGS: The ACTH stimulation test is commonly performed in patients suspected of having adrenal insufficiency when the basal serum cortisol levels are inconclusive. Recent literature has evaluated the impact of technical aspects such as time of the day the test is performed, type of assay and sample source used for cortisol measurement on the clinical value of this test, as well as the feasibility of reliable low dose ACTH testing.

SUMMARY: Clinicians evaluating patients with suspected adrenal insufficiency should take into consideration the clinical presentation (likelihood of adrenal insufficiency before testing) when interpreting the results of the ACTH stimulation test and be aware of clinical and technical factors that can affect cortisol values and diagnostic accuracy of this test.