Growth hormone (GH) analysis for children and adults key information and results

Growth hormone (GH) is one of the most important hormones in the body, responsible for childhood growth and the development of muscles and bones in adults. Measuring this hormone through a GH test helps doctors diagnose growth issues, monitor hormone deficiencies or excesses, and determine the best treatment plans. Whether you are looking for the causes of elevated or low levels, the testing process, or how to accurately interpret the results, this article from Dily Medical provides you with a comprehensive guide to everything you need to know for both children and adults in an easy-to-understand and medically reliable way.With this guide, you’ll learn when the test becomes necessary, how to prepare for it, what abnormal results mean, and the key tips for monitoring your growth hormone health.

1️⃣ What is the Growth Hormone (GH) Test?

The GH test measures the level of Growth Hormone in the blood, which is essential for children's growth and muscle and bone health in adults. It is commonly measured alongside IGF-1 because it is more stable and provides a more accurate reflection of long-term GH activity.

2️⃣ Why is the GH Test Requested?

For Children: To evaluate growth deficiencies or delayed puberty.
For Adults: To diagnose GH deficiency or excess due to pituitary gland issues or tumors.
Sometimes used to monitor the effectiveness of growth hormone replacement therapy.

3️⃣ Does the Test Require Fasting?

❌ Usually, no fasting is required.
✅ Some stimulation tests may require fasting as per the doctor’s instructions.

4️⃣ How to Prepare for the GH Test

Avoid intense physical activity or strenuous exercises before the test.
Inform your doctor about any medications or supplements you are taking.
Ensure good quality sleep before the test for more accurate results.

5️⃣ Difference Between GH and IGF-1

GH: Secreted intermittently throughout the day, so measuring it alone may not be accurate.
IGF-1: A stable protein reflecting long-term GH activity, typically measured with GH to confirm diagnoses.

6️⃣ Is the GH Test Painful or Risky?

❌ No, the test is very safe.
A simple blood sample is drawn from your arm, which may cause mild discomfort or a slight bruise.
During stimulation tests, you may experience temporary headaches or dizziness, which is normal.

7️⃣ When Will Results Be Available?

Results typically appear the same day or the following day, depending on the laboratory.
Stimulation tests may require several hours to monitor GH levels after stimulation.

8️⃣ What Do Abnormal Results Mean in the GH Test?

High Growth Hormone (GH): It may indicate GH overproduction or pituitary tumors.
Low GH: Could suggest GH deficiency due to pituitary problems or chronic illnesses.
✅ Usually confirmed through stimulation tests or IGF-1 measurements before reaching a final diagnosis.

9️⃣ Does GH Affect Growth and Health?

For Children: Essential for normal growth in height, weight, and muscle development.
For Adults: Vital for maintaining muscles, bones, energy, reducing belly fat, and overall health and quality of life.

10️⃣ How is the GH Stimulation Test Done?

The GH Stimulation Test is performed in both children and adults to assess the pituitary gland's ability to release growth hormone.

Steps for the Test:

IV Cannula Placement: An intravenous cannula is placed in the arm or hand for easy blood sampling.
Initial Blood Sample: To measure baseline GH levels before stimulation.
Administration of Stimulant Solution: A substance is given to stimulate the pituitary gland to release GH.
- For Children: Clonidine, Arginine, or Glucagon.
- For Adults: Macimorelin.
Repeated Blood Samples: Typically taken every 30 minutes for about two hours to monitor pituitary response.

Note: Insulin was once used for stimulation but has been excluded due to its impact on blood sugar and hypoglycemia risks.

Common Accompanying Tests:

IGF-1: Reflects GH activity and helps assess bone and tissue growth.
IGFBP-3: A binding protein for IGF-1, providing a more accurate picture of GH activity.

11️⃣ How is the GH Suppression Test Performed?

The GH Suppression Test is used to diagnose GH excess and is also known as the GH Inhibition Test.

Steps for the Test:

Initial Blood Sample: Collected between 6-8 a.m. while fasting.
Glucose Solution: The patient drinks the glucose solution within 5 minutes to induce suppression.
Repeated Blood Samples: Samples are taken over 1-2 hours after drinking the solution, typically 3 samples at intervals of 30-60 minutes.
Analysis: The samples are sent immediately to the lab to measure GH levels after glucose suppression.

Goal: To determine if glucose effectively suppresses GH secretion.

12️⃣ Basic GH Testing Procedure

Because GH levels fluctuate rapidly, doctors often need to collect multiple blood samples over different days to get an accurate picture. It’s usually better to start with IGF-1, as it changes more slowly and reflects long-term GH activity.

1️⃣ GH Stimulation Test:

Fasting for 10-12 hours before the test.
The doctor draws a baseline blood sample while fasting.
A stimulant solution is administered to trigger GH secretion.
Blood samples are typically taken every hour or every 30 minutes for two hours.
The goal is to assess the pituitary gland’s ability to produce adequate growth hormone.

2️⃣ GH Suppression Test:

A baseline blood sample is drawn during fasting (10-12 hours).
The patient drinks a glucose solution.
After two hours, blood is drawn again to monitor glucose's effect on GH suppression.
The goal is to ensure the pituitary is regulating GH levels appropriately.

13️⃣ Normal Growth Hormone (GH) Levels

GH levels vary depending on age and sex, as follows:

Age / Gender	GH Level (ng/mL)
Males (Over 18 years)	0.4 – 5
Females (Over 18 years)	1 – 10
Newborns	5 – 23
1st Week of Life	2 – 27
1 Week – 12 Months	2 – 10
Males (1 – 18 years)	0.4 – 6
Females (1 – 18 years)	1 – 10

✅ Note: These values may slightly vary depending on the laboratory and testing methods, so always interpret the results with your doctor.

1️⃣ Types of Growth Hormone (GH) Tests

The Growth Hormone (GH) test varies based on age and the purpose of the test. Here are some common types:

1️⃣ Basal GH Test

Concept: Measures the GH level in the blood at a random time.

Usage:
- For Children: To evaluate growth deficiencies or noticeable short stature.
- For Adults: To assess GH deficiency after pituitary gland problems.
Notes:
- GH is secreted intermittently, so this test alone may not provide accurate results.
- Often combined with IGF-1 measurement to assess actual hormone activity.

2️⃣ GH Stimulation Tests

Concept: Stimulates the pituitary gland to release GH using specific substances.

Common substances used:
- Arginine
- Clonidine
- Glucagon
- Insulin (for hypoglycemic stimulation test)
Usage:
- For Children: To confirm GH deficiency in cases of short stature or poor growth.
- For Adults: To confirm GH deficiency after pituitary tumors or surgeries.
Notes:
- Blood samples are taken at specific intervals after stimulation.
- Provides more accurate results than a random test.

3️⃣ IGF-1 Test (Insulin-like Growth Factor 1)

Concept: Measures the IGF-1 protein secreted by the liver in response to GH.

Usage:
- Often used in conjunction with basal GH or stimulation tests.
- IGF-1 is more stable than GH and reflects long-term GH activity.
Notes:
- Useful for diagnosing GH deficiency or excess.
- Levels vary based on age and sex.

4️⃣ IGFBP-3 Test (IGF Binding Protein 3)

Concept: A protein that binds to IGF-1 and provides additional insight into GH activity.

Usage:
- Often used in children when GH deficiency is suspected.
Notes:
- Used as a supportive marker, not a final diagnosis on its own.

2️⃣ Uses of Growth Hormone (GH) Test

Growth Hormone (GH), secreted by the pituitary gland in the brain, plays a significant role in:

Growth in Children
Muscle Development
Metabolism and Organ Health

The GH test is medically used to diagnose and monitor several conditions, as follows:

1️⃣ Diagnosing Growth Hormone Deficiency

In Children:
- Delayed growth or short stature
- Poor weight or muscle gain
In Adults:
- Severe fatigue
- Weak muscles
- Increased belly fat
Test Purpose: To ensure the body is secreting adequate levels of GH.

2️⃣ Diagnosing Growth Hormone Excess (Acromegaly)

In Adults: Excess GH can lead to:
- Enlarged hands and feet
- Changes in facial features (jaw, forehead)
- Joint and muscle problems
Test Purpose: To detect early GH overproduction and monitor treatment following pituitary tumor removal or medical therapy.

3️⃣ Monitoring Growth Hormone Treatment

Some children or adults receive GH therapy to correct deficiency or stimulate growth.
The test helps the doctor to:
- Confirm the appropriate dosage
- Assess how well the body is responding to the treatment

4️⃣ Evaluating Metabolic Disorders

GH deficiency or excess can affect:
- Fat and muscle levels
- Blood sugar levels
- Cardiovascular health
The test helps doctors to identify the cause and manage complications.

3️⃣ Steps in the GH Test

1️⃣ Before the Test

Fasting: Usually 8–12 hours before the test.
Rest: Avoid stress and intense physical exertion.
Medications: Inform your doctor about any medications or supplements you're taking as some may affect results.
Sleep: Getting good sleep the night before is essential, as GH levels are influenced by sleep.

2️⃣ During the Test

Blood Sample: A blood sample is drawn from a vein in the arm using a sterile syringe.
Stimulative Test (if required): The patient receives a substance to stimulate GH release, and blood samples are taken at specific intervals to monitor the pituitary gland’s response.

3️⃣ After the Test

Place a cotton swab on the injection site for a few seconds to avoid bruising.
You can return to normal activities immediately unless otherwise advised by the doctor.

4️⃣ At the Laboratory

The serum is separated from the blood.
GH levels are measured using precise chemical or enzymatic methods.
IGF-1 may also be measured as a more stable marker of GH activity.

4️⃣ Risks of the Growth Hormone (GH) Test

The GH test is very safe as it involves drawing a blood sample from the arm, but there are some minimal risks or observations:

1️⃣ Blood Draw Risks

Minor bruising or swelling at the injection site
Mild discomfort or tingling during the blood draw
Rarely: slight bleeding

2️⃣ Risks of Stimulation Tests

Some stimulation tests use substances that increase GH secretion, and they may cause:
- Light dizziness
- Temporary nausea
- Mild headache
These symptoms usually resolve quickly after the test.

3️⃣ Risks for People with Medical Conditions

People with heart problems or severe hypertension may need monitoring during stimulation tests.
Always inform your doctor about any chronic conditions or medications before the test.

4️⃣ Indirect Risks

False or inaccurate results if the sample is not correctly handled.
Intense physical activity before the test may affect results.
Medications affecting GH can interfere with test outcomes, and a retest may be necessary.

5️⃣ Causes of High Growth Hormone (GH) Levels

1️⃣ Pathological Causes

Excess GH in Adults: Often due to pituitary tumors → causes Acromegaly (enlargement of hands and feet, facial changes, joint and muscle problems).
Excess GH in Children: Leads to Gigantism (excessive height growth) usually due to pituitary tumors.
Chronic liver or kidney diseases can affect GH secretion.

2️⃣ Natural or Temporary Causes

Deep sleep (GH is secreted more during sleep)
Intense physical exercise
Psychological stress or anxiety
Fasting or long-term starvation
These elevations are usually temporary and return to normal levels.

3️⃣ Testing Causes (False Elevation)

Blood draw errors or improper sample storage
Use of certain medications like steroids or some diabetes medications
Certain stimulatory tests can naturally increase GH levels temporarily.

6️⃣ Growth Hormone (GH) Test Results

Since GH is secreted in pulses, it is often measured alongside IGF-1 to give a more accurate picture of GH activity over time.

Normal Values

Adults: 0.4 – 10 ng/mL
Children: Varies based on age and growth stage

High GH Levels

May indicate:
- Excess GH in Adults → Enlargement of hands and feet, changes in facial features, joint problems.
- Excess GH in Children → Excessive height growth.
If part of a stimulation test, results are compared to standard thresholds to determine normal or excessive response.

Low GH Levels

May indicate:
- In Children: Growth delays, short stature, poor muscle or weight gain.
- In Adults: Severe fatigue, muscle weakness, increased belly fat.
Typically, a stimulation test is requested to confirm GH deficiency.

Important Notes:

GH is secreted in pulses, so a single measurement may not be sufficient.
IGF-1 is usually measured alongside GH as it provides a more stable and accurate assessment of GH activity.
Test results should be interpreted based on the patient’s symptoms, age, and any necessary stimulation tests.

7️⃣ Reasons for Low GH Levels

1️⃣ Pathological Causes

GH deficiency due to pituitary gland problems or tumors.
Chronic diseases like severe liver or kidney conditions, malnutrition.

2️⃣ Natural or Temporary Causes

Aging (GH secretion decreases gradually).
Poor sleep or sleep disorders.
Severe stress or acute illnesses.

3️⃣ Testing Causes (False Lowered Results)

Blood sample taken at the wrong time (since GH is secreted intermittently).
Medications like steroids or some diabetes drugs affecting GH secretion.
Errors in blood sample collection or storage.

8️⃣ Growth Hormone (GH) Test Values (Approximate)

Category	GH Level (ng/mL)	Notes
Children	0.0 – 10	Varies based on age, sex, and growth stage
Adolescents	0.0 – 10	Before closure of growth plates
Adults	0.4 – 10	Depends on lab and testing methods