A growth hormone test checks whether the pituitary gland is making too little or too much growth hormone. Because the hormone is released in short bursts and is almost undetectable between them, a random blood sample is not useful.
Testing therefore relies on IGF-1, a stable blood marker made in response to growth hormone, and on dynamic tests: stimulation tests to look for deficiency and a glucose suppression test to look for excess (acromegaly).
What Growth Hormone Test shows
In children, the tests help explain short stature or slowing growth by showing whether the pituitary can release enough growth hormone when provoked. In adults, they confirm deficiency after pituitary tumours, surgery, radiotherapy or head injury. A raised IGF-1 with failure of growth hormone to fall after a glucose drink confirms acromegaly, the condition of excess hormone that enlarges hands, feet and facial features. Results are always read alongside growth charts, bone age X-ray, other pituitary hormones and a pituitary MRI.
When Growth Hormone Test is recommended
- A child who is well below expected height or whose growth has crossed centile lines downward
- A child with a known pituitary or midline brain condition, or after cranial radiotherapy
- Adults with pituitary disease and symptoms such as fatigue, reduced muscle and increased fat
- Enlarging hands, feet, jaw or spaced teeth, sweating and joint pain suggesting acromegaly
- Monitoring of treatment for acromegaly or of growth hormone replacement
Limits and situations where another test is better:
- Short but normally growing children with short parents usually need no stimulation test
- Testing for anti-ageing, bodybuilding or wellness purposes has no medical basis
- Results are unreliable in untreated hypothyroidism, poor nutrition or significant obesity
- Insulin tolerance tests are avoided in people with epilepsy or heart disease and in small children in many centres
How to prepare
- Fast from midnight; water is allowed
- Children may need sex hormone priming a few days before, as the specialist advises
- Tell the team about steroids, oestrogen and other regular medicines
- Bring growth records, parental heights and any previous bone age X-ray
- Plan for a half day in the unit and bring a snack for afterwards
What happens during the test
A cannula is placed in a vein so that several samples can be taken without repeated needles. For a stimulation test, a provoking agent such as glucagon, arginine, clonidine or insulin is given and blood is drawn every 30 minutes for 2 to 4 hours. A nurse stays with you, and with a child a parent stays throughout. For suspected acromegaly you drink a glucose solution and samples are taken over 2 hours.
Results and next steps
IGF-1 takes a few days. Stimulation results are usually ready within a week. Deficiency in children normally requires failure on two different stimulation tests. If deficiency is confirmed, the specialist discusses daily or weekly growth hormone injections. If excess is confirmed, a pituitary MRI and referral to a pituitary surgeon follow.
- Test time: 2 to 4 hours
- Results ready: 3 to 7 days
- Back to everyday activity: Rest of the day after stimulation tests
Safety and risks
- Nausea, vomiting or drowsiness with glucagon or clonidine
- Low blood sugar during an insulin tolerance test, which is why it is closely supervised
- Low blood pressure and sleepiness after clonidine
- Bruising at the cannula site
- Borderline results that need repeating
Arranging Growth Hormone Test in Türkiye
These tests can be done within a 2 to 3 day visit together with a pituitary MRI and an endocrine opinion. Think carefully before travelling for a child's growth assessment, though. Growth hormone treatment lasts years, with injections, dose changes and clinic measurements every 3 to 6 months, so the treating team needs to be close to home. A visit is best used for diagnosis or a second opinion.
Send your previous reports and the question you want answered and a Clinic-Y coordinator replies within 24 hours with suitable teams and written, all-inclusive proposals side by side. Reviewing your case is free.
Frequently Asked Questions
Why can't you just measure growth hormone once?
Levels are near zero most of the day in healthy people, so a low random value proves nothing.
Is the test safe for children?
Yes when done in an experienced unit with continuous supervision. Sleepiness and nausea are the usual side effects.
Does a failed test mean lifelong injections?
Not always. Many children with isolated deficiency are retested at the end of growth, and a proportion no longer need treatment.
Can adults take growth hormone for fitness or ageing?
That is not an approved or safe use. It raises the risk of diabetes, joint pain and fluid retention, and is banned in sport.