ACTH Stimulation Test for Adrenal Insufficiency with Free Cortisol Levels

Assay for Cortisol:

Electrochemiluminescence immunoassay (ECLIA) .

Precautions:

Cosyntropin is category C of pregnancy.

Interpretation:

Normal response: Peak stimulated cortisol value > 1.2 mcg/dl [3, 4] at 30 or 60 min. Most subjects achieve higher cortisol levels at 60 min compared to the 30 min value following 250 mcg of cosyntropin administration.

Caveats:

This cut-off value may not apply to ICU patients. Further studies are needed to establish appropriate levels in such patients. Benefit from glucocorticoid therapy may be beyond adrenal function status in patients with septic shock [1]
Free cortisol index (FCI) may be used as an alternative to this dynamic test, if free cortisol assay is not available.
FCI: Total cortisol (nmol/L)/CBG (mg/dl) < 12 suggests adrenal insufficiency [5]. Total cortisol should be measured in the morning between 8–10 am.

Procedure:

Completed as outpatient

Draw blood sample for baseline serum free cortisol.

Give Cortrosyn 250 mcg IM.

Only gold members can continue reading. Log In or Register to continue