What is the 17-Hydroxyprogesterone Test?

The 17-hydroxyprogesterone (17-OHP) test measures the level of a steroid hormone produced by the adrenal glands and, to a lesser extent, the ovaries and testes. It is an intermediate hormone in the pathway that leads to cortisol production.

When the enzymes involved in cortisol synthesis do not function properly, 17-OHP can accumulate in the blood. This accumulation is most commonly seen in congenital adrenal hyperplasia (CAH), a genetic condition affecting adrenal hormone production. Measuring 17-OHP provides critical insight into how efficiently the adrenal glands are functioning.

The test is used in both children and adults to investigate adrenal disorders, androgen excess and certain fertility or menstrual abnormalities.

Why do I need a test for 17-Hydroxyprogesterone?

You may need this test if there is suspicion of abnormal adrenal hormone production. Elevated 17-OHP levels can indicate impaired cortisol synthesis, which may lead to excess androgen production and a wide range of clinical symptoms.

In adults, the test is often used to investigate unexplained hormonal symptoms such as irregular periods, infertility or signs of androgen excess. In newborns and children, it plays a key role in screening and diagnosing congenital adrenal hyperplasia.

Symptoms and scenarios where testing is recommended:

• Suspected congenital adrenal hyperplasia
• Irregular or absent menstrual cycles
• Excess facial or body hair (hirsutism)
• Acne resistant to standard treatment
• Infertility or ovulation problems
• Early or delayed puberty
• Ambiguous genitalia in newborns
• Adrenal hormone imbalance on other tests
• Monitoring known adrenal disorders

Benefits of the 17-Hydroxyprogesterone Test

• Key diagnostic marker for congenital adrenal hyperplasia
  Essential for identifying enzyme defects affecting cortisol synthesis.
• Assesses adrenal gland hormone pathways
  Provides insight into how effectively cortisol is being produced.
• Helps explain androgen excess symptoms
  Elevated levels can clarify causes of acne, hirsutism and cycle irregularities.
• Supports fertility and menstrual investigations
  Useful in assessing hormonal causes of ovulatory dysfunction.
• Used in both paediatric and adult medicine
  Applicable from newborn screening through adulthood.
• Guides further endocrine testing
  Results help determine whether genetic or stimulation testing is required.
• Supports long-term monitoring of adrenal disorders
  Helps track disease control and treatment effectiveness.
• Simple but highly informative blood test
  Requires only a standard blood sample with significant diagnostic value.

Step-by-Step: How Testing Works

Choose your preferred testing method

You can attend one of our UK partner clinics or arrange a home or hotel visit with a mobile phlebotomist.

Option 1 – In-Clinic Blood Draw

1. Select your nearest UK clinic and book an appointment.
2. A clinician or phlebotomist collects a venous blood sample, often in the morning.
3. The sample is analysed for 17-hydroxyprogesterone levels.
4. Results are delivered securely online.

Option 2 – Home or Hotel Phlebotomy (+£60)

1. Book a UK-wide home or hotel visit at a convenient time.
2. A trained phlebotomist collects your blood sample on-site.
3. The sample is packaged and transported promptly to the laboratory.
4. Results are uploaded digitally without the need to travel.

Access your report

You can download and share your results with your GP or endocrinologist for interpretation.

Your Results Explained

Low Levels

Low 17-hydroxyprogesterone levels are generally considered normal.
They suggest normal cortisol synthesis and balanced adrenal hormone production.

Typical UK reference range: varies by age, sex and menstrual phase, often <6 nmol/L in adults.

Normal Levels

Normal results indicate appropriate adrenal enzyme function and cortisol pathway activity.
This makes congenital adrenal hyperplasia or significant adrenal dysfunction unlikely.

High Levels

Elevated 17-OHP levels indicate impaired cortisol synthesis, most commonly due to congenital adrenal hyperplasia.
High levels may also be seen in adrenal tumours or severe stress states.
Results often prompt further endocrine testing, including ACTH stimulation or genetic analysis.