17-hydroxyprogesterone (17-OHP) is used in the diagnosis and monitoring of congenital adrenal hyperplasia (CAH) due to 21-hydroxylase deficiency and in the identification of heterozygotes and diagnosis of mild, also referred to as late-onset and cryptic forms of CAH.
Clinical indications for testing include:
- ambiguous genitalia (female infants)
- "salt-wasting" clinical symptoms (dehydration, vomiting, listlessness)
- precociousness or failure of puberty
- anovulation/menstrual irregularity
All new CAH cases should be confirmed with a urine steroid profile.
Diagnosis of CAH
- Samples should be taken at least 48 hours after birth or levels will be falsely raised.
- Take blood before any emergency administration of corticosteroids and preferably in the early morning.
- Please contact the duty biochemist if the child is acutely unwell so that arrangements can be made for sample processing as soon as possible with the assaying laboratory.
- For identification of heterozygotes and diagnosis of mild congenital adrenal hyperplasia, samples should be collected early morning, in the follicular phase of cycle (first 5 days following menstruation) and off the pill,
Monitoring response to treatment
- Take blood between 8:00h and 9:00h before initiation of treatment and again 2h after the first dose of corticosteroid.
- Further samples may be taken throughout the day. Record the time of any therapy.
- Adequacy of therapy may be better judged if combined with measurement of androstenedione.
For adults, blood taken into a 5mL gold top tube (or rust top for the Acute Unit)
For children, blood taken into a 3.5mL rust top tube
For neonates (> 48h after birth), blood taken into a 0.8mL lithium heparin minicollect tube.
Send at ambient temperature to the laboratory. If unavoidable, samples can be stored refrigerated overnight.
Relevant clinical details including signs of hyperandrogenism, electrolyte status, time of cycle if menstruating.
Samples are sent for analysis to King's College Hospital, London with a result expected within 2 weeks.
However, if a child is acutely unwell please alert the duty biochemist so that special arrangements can be made with the assaying laboratory to obtain a result more quickly.
Results should be interpreted in light of clinical presentation, Tanner stage and sex of patient. Reference ranges will be provided with the report. Please speak to the duty biochemist with any queries.
- Raised levels are common in premature/stressed infants.
- Levels above 50 nmol/L are diagnostic of CAH.
- If the baseline 17- OHP is elevated >10nmol/L, a synacthen test may be indicated to confirm or exclude late onset congenital adrenal hyperplasia.
To learn more about 17-hydroxyprogesterone visit Lab Tests Online
Endobible also provides a useful source of information for health professionals for investigation and management of endocrine conditions.
Page last updated: 20/04/2021