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Bloodspot 17-hydroxyprogesterone; 17-OHP

Monitoring of patients with Congenital Adrenal Hyperplasia (CAH)

Pseudonyms: 17α-hydroxyprogesterone (17α-OHP), 17α-hydroxypregn-4-ene-3,20-dione

General information

Collection Container: Bloodspot card

Type and volume of sample: Two bloodspot samples should be collected at three different times throughout one day (six bloodspots in total)

Specimen transport/special precautions: Patients are instructed to collect free flowing blood from a finger prick on to Perkin Elmer 226 filter paper and note the time of collection.

Laboratory information

Method principle: 17α-OHP is analysed using a competitive solid phase time-resolved fluoroimmunoassay.  

Biological reference range: N/A - for monitoring purposes only

Turnaround time: 1 month

Clinical information

There are various congenital enzyme defects of the steroid biosynthesis which cause congenital adrenal hyperplasia (CAH).

They are genetically different, but are all transmitted in an autosomal recessive mode.  The most frequent types are the 21-hydroxylase deficiency (>90% of cases) and the 11β-hydroxylase deficiency (approx 5-8% of all cases).  17α-OH-progesterone, a precursor of cortisol, is increased in both 21- and 11β-hydroxylase deficiency, but not in other types:


Steroidogenesis: The enzymes affected in CAH are represented by one red and four green bars on the top half of the diagram

Cross-reactivity with other steroids:

Substance Cross-reactivity %
17α-Hydroxypregnenolone sulfate 2.0
11-Deoxycortisol 1.82
17α-Hydroxypregnenolone 1.20
Progesterone 0.47
21-Deoxycortisol 0.46
Deoxycorticosterone 0.09
Sprionolactone 0.09
Pregnenolone < 0.09
Cortisone < 0.09
Cortisol < 0.09
Prednisolone < 0.09
5ß-Dihydrocortisol < 0.09
Prednisone < 0.09
Dexamethasone < 0.09
5ß-Dihydrocortisone < 0.09
Testosterone < 0.09
ß-Estradiol < 0.09
Estriol < 0.09
Dehydroisoandrosterone < 0.09
16αHydroxypregnenolone < 0.09
20α-Dihydroprogesterone < 0.09

Factors known to significantly affect the results:

Do not use blood collected into EDTA or citrate tubes as these anticoagulants will affect the assay by chelating the europium label.

Poor spot quality will affect the results obtained. Samples that are not uniformly saturated with blood, poorly collected, improperly dried or contaminated samples reported as insufficient for analysis.


(Last reviewed 29th February 2016)