Function tests

Suspicion of adrenogenital syndrome due to 21-hydroxylase-deficiency.

(Please be aware that there are different test procedures for the exclusion of 3-beta-hydroxy steroid dehydrogenase as well as for 11-beta-hydroxylase deficiency.)

As long as the basal (unstimulated) value for 17-hydroxy-progesterone (17-OHP) is < 2 µg/l, an AGS can largely be ruled out and a stimulation with ACTH (Synacthen) is only necessary in extreme exceptional cases. A basal 17-OHP > 10 µg/l alone already justifies diagnosis of AGS, which should be further confirmed by human genetic testing. Stimulation is also dispensable in this case. In case of basal 17-OHP ranging between 2 – 10 µg/l, the diagnosis can be made by the ACTH stimulation test.

17-OH-progesterone

2 – 5 ml whole blood without supplements, before and 60 min after ACTH-administration. Centrifuge blood after 30 - 40 min and send in serum.

The test should be done during the proliferative stage of the adult woman to avoid interpretation problems, which can occur during raised progesterone-levels.

Obligatory test start between 7 and 9 o’clock. The patient should be empty-stomached for the duration of the test.

1. Initial basal blood extraction prior to ACTH administration.
2. Intravenous injection of ACTH (Synacthen® 0,25) (250 µg = 25 IE ACTH) as a bolus.
3. Blood extraction after 60 min. (Additional blood extraction after 30 min can assist evaluation but is not essential). Mark the samples with the extraction timings and send to the laboratory for evaluation of 17-OH-progesterone.

If the 17-OH-progesterone value remains < 10 µg/l, an AGS can be ruled out. If the value rises to > 10 µg/l there is a strong suspicion of AGS, which should be secured by human genetic testing.