17-Hydroxyprogesterone Test: Guide for Canadians (2025)

A 17-hydroxyprogesterone test is a simple blood test that measures a key hormone produced by your adrenal glands. Doctors across Canada use this test to help diagnose congenital adrenal hyperplasia (CAH), a condition that affects how the body produces cortisol and other essential hormones. The test can be performed on newborns, children, and adults alike.

How the 17-Hydroxyprogesterone Test Works and What to Expect

Understanding your 17-OHP blood test results and knowing when this screening is needed can help you have a more informed conversation with your family doctor or healthcare provider. Whether you are a parent concerned about newborn screening or an adult experiencing unusual symptoms, this guide explains everything Canadians need to know about the test, including preparation, normal ranges, and what high levels may indicate.

What Is 17-Hydroxyprogesterone?

Types of Congenital Adrenal Hyperplasia Detected by the 17-Hydroxyprogesterone Test

Type	Characteristics	17-OHP Levels	Management
Classic Salt-Wasting CAH	Severe cortisol and aldosterone deficiency; life-threatening adrenal crisis possible in newborns; ambiguous genitalia in females	Markedly elevated (often >100 nmol/L)	Immediate glucocorticoid and mineralocorticoid replacement; lifelong hormone therapy; monitored by pediatric endocrinologist
Classic Simple-Virilizing CAH	Cortisol deficiency without significant salt loss; virilization in females; early puberty in males	Significantly elevated (typically 30–100 nmol/L)	Glucocorticoid replacement therapy; surgical consultation may be required; regular endocrine follow-up
Non-Classic (Late-Onset) CAH	Milder enzyme deficiency; presents in childhood or adulthood; symptoms include acne, irregular periods, and excess hair growth	Mildly to moderately elevated (10–30 nmol/L)	Low-dose glucocorticoid therapy if symptomatic; monitoring without treatment in asymptomatic cases
Cryptic (Asymptomatic) CAH	Biochemical abnormality with no clinical symptoms; often identified incidentally through family screening or genetic testing	Mildly elevated or borderline (6–10 nmol/L)	Regular monitoring recommended; treatment typically not required unless symptoms develop
Normal / Unaffected	No adrenal enzyme deficiency; typical cortisol and aldosterone production; no signs of virilization or adrenal insufficiency	Within reference range (<6 nmol/L in most labs)	No treatment required; routine well-child or adult care as appropriate per Canadian clinical guidelines

17-hydroxyprogesterone (often written as 17-OHP) is a hormone produced by the adrenal glands — two small glands that sit on top of your kidneys. It acts as a building block for making cortisol, which is one of the body’s most important stress hormones.

Cortisol does several critical jobs. It helps regulate blood sugar, reduces inflammation, and supports your immune system. When the body cannot properly convert 17-OHP into cortisol, levels of 17-OHP build up in the blood. This build-up is a key sign that something is interfering with normal hormone production.

In addition, 17-OHP is linked to the production of other hormones, including androgens (male sex hormones that both men and women produce). An excess of these androgens can cause symptoms like unwanted hair growth and irregular periods in women.

Why the 17-Hydroxyprogesterone Test Is Ordered

Your doctor may order a 17-hydroxyprogesterone test for several reasons. The most common reason is to check for congenital adrenal hyperplasia (CAH), a genetic condition present from birth.

However, the test is also useful for adults who are showing symptoms that suggest a hormonal imbalance. Here are the most common reasons a doctor might recommend this test:

• Newborn screening: In Canada, many provinces include CAH in their newborn screening programmes. Early detection is important because CAH can be life-threatening if left untreated in infants.
• Hirsutism in women: This means excess hair growth on the face, chest, or back. It can be a sign that androgen levels are too high.
• Irregular menstrual cycles: Women with unexplained irregular periods may be tested to rule out CAH as an underlying cause.
• Infertility: Both men and women being investigated for infertility may benefit from this test, particularly if there is a family history of CAH.
• Ambiguous genitalia in newborns: When a baby’s sex characteristics are not clearly defined at birth, this test can help identify hormonal causes.
• Puberty concerns: Early or delayed puberty can sometimes be linked to adrenal gland conditions that this test can help identify.

Furthermore, if someone in your immediate family has been diagnosed with CAH, your doctor may recommend genetic counselling and testing for you as well. Health Canada supports newborn screening programmes across provinces as part of early disease detection efforts.

Understanding Congenital Adrenal Hyperplasia (CAH)

What Is CAH?

Congenital adrenal hyperplasia is a group of inherited disorders that affect the adrenal glands. The adrenal glands cannot produce enough cortisol because key enzymes are missing or not working properly. As a result, the glands work harder and grow larger — which is what “hyperplasia” means.

About 90% of all CAH cases are caused by a mutation in the CYP21A2 gene. This gene provides instructions for making an enzyme called 21-hydroxylase. Without this enzyme, the body cannot complete the steps needed to produce cortisol and aldosterone (a hormone that helps regulate salt and water balance).

Two Forms of Enzyme Deficiency

Elevated 17-OHP levels are most often linked to deficiencies in two specific enzymes:

• 21-hydroxylase deficiency: The most common cause of CAH. It accounts for the vast majority of cases worldwide.
• 11-beta-hydroxylase deficiency: A less common but significant cause of CAH that also raises 17-OHP levels.

When either of these enzymes is deficient, 17-hydroxyprogesterone cannot be properly converted, so it accumulates in the blood. Therefore, a high test result is a strong indicator that one of these enzyme deficiencies may be present.

Symptoms of CAH

Symptoms of congenital adrenal hyperplasia can vary widely from person to person. They may develop gradually over time, or they may be present at birth.

Common symptoms include:

• Early or unusual puberty
• Rapid growth in childhood, but shorter-than-average adult height
• Excess body or facial hair in females (hirsutism)
• Irregular or absent menstrual periods
• Acne
• Infertility in both men and women
• Fatigue and low blood pressure (in more severe cases)

If CAH goes untreated, it can significantly affect a child’s growth, development, and puberty. In adults, untreated CAH can lead to fertility problems and ongoing hormonal imbalances. For more information on adrenal gland disorders, visit Mayo Clinic’s guide to congenital adrenal hyperplasia.

How the 17-Hydroxyprogesterone Test Works

How to Prepare for the Test

Preparation for the 17-hydroxyprogesterone test is straightforward, but timing matters. Your doctor will likely ask you to have blood drawn in the morning. This is because 17-OHP levels follow a daily pattern and are typically highest in the early morning hours.

For women, the test should ideally be done during the follicular phase of the menstrual cycle — that is, within the first 10 days after your period begins. Hormone levels shift throughout the menstrual cycle, so testing at the right time helps ensure the most accurate result.

In addition, if you are feeling unwell or under significant stress, your cortisol levels may be temporarily elevated. Let your doctor know, as this can affect how results are interpreted.

How the Test Is Performed

The test involves a simple blood draw, usually from a vein in your arm. The sample is then sent to a lab for analysis. In most cases, the lab uses a method called ELISA (enzyme-linked immunosorbent assay) to measure hormone levels in the blood. This is a well-established and reliable laboratory technique.

For newborns, the test is typically done using a heel prick blood sample as part of routine newborn screening. Results are usually available within a few days.

Understanding Your Results

Normal 17-OHP levels vary depending on age, sex, and the phase of the menstrual cycle. Your doctor will compare your results against reference ranges provided by the laboratory.

In general:

• Normal levels suggest no enzyme deficiency is present.
• Mildly elevated levels may indicate a non-classic (mild) form of CAH or prompt further testing.
• Significantly elevated levels strongly suggest classic CAH and will lead to additional investigation and treatment planning.

However, it is important not to interpret results on your own. Your doctor will look at your results alongside your symptoms, medical history, and possibly other hormone tests. According to Healthline’s overview of hormone testing, context is essential when evaluating hormonal lab results.

Who Should Be Tested?

The 17-hydroxyprogesterone test is recommended in several specific situations. Your family doctor or a specialist (such as an endocrinologist or gynaecologist) may suggest testing if you fall into one of the following groups:

• Women with hirsutism: Unexplained excess hair growth is one of the most common reasons for ordering this test in adult women.
• Women with irregular periods: Especially when other causes like polycystic ovary syndrome (PCOS) have been ruled out.
• Men with unexplained infertility: Particularly if there is a known family history of CAH.
• Newborns: As part of provincial newborn screening programmes.
• Children with early puberty: If a child is showing signs of puberty much earlier than expected.
• People with a family history of CAH: Genetic carriers may have mildly elevated levels and benefit from monitoring.

In Canada, access to this test is available through a referral from your family doctor or a specialist. If you have concerns, speak with your healthcare provider about whether this test is appropriate for your situation.

When to See a Doctor

You should speak with your family doctor if you or your child is showing any of the symptoms described above — particularly unexplained hair growth, irregular periods, early puberty, or fertility difficulties. These symptoms do not always mean CAH is present, but they do warrant a proper evaluation.

If you do not have a family doctor, a walk-in clinic is a good first step. A walk-in physician can order initial blood work, including the 17-hydroxyprogesterone test, and refer you to a specialist if needed. Most provinces cover this type of diagnostic testing under their provincial health plans, so the cost should be minimal or covered entirely.

If a newborn is showing signs of illness shortly after birth — such as poor feeding, vomiting, or extreme fatigue — seek emergency care right away. These can be signs of a severe form of CAH called a “salt-wasting crisis,” which requires immediate medical attention.

Always consult a qualified healthcare provider before drawing any conclusions from your test results. Only a doctor can properly interpret hormone levels in the context of your full health picture.

Frequently Asked Questions

Key Takeaways

• The 17-hydroxyprogesterone test is a blood test used to detect problems with adrenal gland hormone production.
• It is the primary tool for diagnosing congenital adrenal hyperplasia (CAH), a genetic condition affecting cortisol production.
• About 90% of CAH cases are caused by a mutation in the CYP21A2 gene, which affects the 21-hydroxylase enzyme.
• The test is recommended for women with hirsutism or irregular periods, men with unexplained infertility, and newborns as part of provincial screening programmes.
• For the most accurate results, women should be tested in the morning during the first 10 days of their menstrual cycle.
• If you have symptoms of a hormonal imbalance, speak with your family doctor or visit a walk-in clinic. Most provincial health plans cover diagnostic hormone testing.
• Never interpret hormone test results on your own — always work with a qualified healthcare provider for a proper diagnosis and treatment plan.