use aldosterone and ACTH to differentiate between primary and secondary adrenal insufficiency

• related: adrenal insufficiency
• tags: #permanent

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When cosyntropin stimulation test returns with low cortisol (<18), you have adrenal insufficiency. However, this does not tell you whether you have primary (adrenal gland not working) or secondary (pituitary not working) adrenal insufficieny.

In this case, you can use aldosterone or ACTH to determine which adrenal insufficiency there is. In primary adrenal insufficiency, am ACTH would be high. In secondary or tertiary adrenal insufficiency, am ACTH would be low or inappropriately normal.¹

Links to this note

• adrenal insufficiency
  • use aldosterone and ACTH to differentiate between primary and secondary adrenal insufficiency

Footnotes

1. https://www.uptodate.com/contents/diagnosis-of-adrenal-insufficiency-in-adults?source=autocomplete&index=0~2&search=adrenal ↩