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.
Testing:
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
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Stimulated 17-OHP
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Seen in:
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< 200
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general population
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200-500
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overlap of normal or heterozygous
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500-1,000
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mostly heterozygous but occasional normal
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1,000-1,200
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heterozygous
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1,200-12,590
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variant deficiency
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> 12,590
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classical deficiency
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