Pituitary axis
ACTH
Anterior pituitary corticotroph hormone driving adrenal cortisol synthesis.
Sample
EDTA plasma, on ice
Stability
Highly labile — transport on ice, spin and freeze within 30 min.
Clinical reference range
7.2 to 63 pg/mL
Morning adult
Conv: 7.2–63 pg/mL
Biology
What it measures
POMC-derived; stimulates adrenal zona fasciculata cortisol synthesis. Diurnal rhythm peaks ~6–8 AM.
Clinical use
Why we order it
Differentiating ACTH-dependent from ACTH-independent Cushing's; primary vs central adrenal insufficiency.
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