The short ACTH stimulation test is used to evaluate patients with congenital adrenal hyperplasia due to biosynthetic defects. This is primarily a screening test and cannot exclude people with heterozygous defects in biosynthesis. Cosyntropin is a synthetic ACTH analogue with activity very similar to native ACTH.


Patient Preparation and Specimen Collection:

After an overnight fast, a serum sample is collected. Immediately afterwards, an injection of 250 micrograms of cosyntropin (Cortrosyn) is given IV (suspended in 2-5 mL of sterile normal saline) or IM. Additional serum samples are collected 30 and 60 minutes after the injection. Women being tested for 21-hydroxylase deficiency should be tested during the follicular phase of the menstrual cycle.



Samples can be tested for adrenal steroids (17-hydroxyprogesterone, delta-4-androstenedione, 17-hydroxypregnenolone, 11-deoxycortisol) if congenital adrenal hyperplasia is to be evaluated.


Diagnosis of adrenal hyperplasia associated with 21-hydroxylase deficiency :

(1) Basal 17-hydroxyprogesterone levels > 200 ng/dL with peak levels after stimulation > 1200 ng/dL are consistent with 21-hydroxylase deficiency

(2) Nomograms exist for evaluating basal vs stimulated 17-hydroxyprogesterone

(3) The regression line for the 60 minute nomogram is:


LOG10(stimulated 17-OHP) =

= (0.6857 * LOG10(baseline 17-OHP)) + 1.48018


stimulated 17-OHP =

= ((baseline 17-OHP) ^ 0.6857) * (10 ^ 1.48018) =

= ((baseline 17-OHP) ^ 0.6857) * 30.212

Stimulated 17-OHP

Seen in:

< 200

general population


overlap of normal or heterozygous


mostly heterozygous but occasional normal




variant deficiency

> 12,590

classical deficiency


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