17α - Hydroxyprogesterone
Diagnosis of congenital adrenal hyperplasia (CAH) due to
21-hydroxylase deficiency. Levels may be measured following
stimulation with ACTH (Synacthen) in investigation of late onset
(or mild) CAH. May also be useful in monitoring response to
corticosteroid therapy in CAH due to 21-hydroxylase deficiency.
Combined Pathology Blood form (Yellow/Black)
Analysed by referral laboratory if specific criteria met.
Investigation or monitoring of CAH
Serum or Plasma
Yellow top (SST) tube or Paediatric Red top
Take blood before emergency administration of corticosteroids
and preferably early morning. Samples should not be taken in
newborn infants until more than 48 hours after birth.
In monitoring response to treatment, take blood between 08.00h and
09.00h before initiation of treatment for day and again 2 hours
after first dose of corticosteroid.
Blood should be taken basal and at 30 minutes and 60 minutes
Aliquot and store at 4C
Causes for Rejection
Sample from newborn less than 48 hours after birth
Infants >5 days and adults: less than 20 nmol/L
Peak levels following Synacthen: Less than 35 nmol/L excludes
CAH, whilst a level greater than 60 nmol/L is consistent with CAH.
Levels between 35 and 60 are borderline.