Description: A growth hormone test is going to measure the amount of growth hormone in the body. It is used to determine if a person is deficient in growth hormone causing slowed growth. Less commonly, it can be used to determine if there is too much growth hormone causing gigantism or acromegaly.
Also Known As: GH Test, Growth Hormone GH, HGH Test, Human Growth Hormone (hGH), Somatotropin, Growth Hormone Stimulation Test
Collection Method: Blood Draw
Specimen Type: Serum
Test Preparation: Patients should be fasting and have rested for at least 30 minutes prior to collection.
When is a Growth Hormone test ordered?
When a kid exhibits the following signs and symptoms of growth hormone insufficiency, GH testing is recommended.
- A child's growth rate is slowed in early life
- Delay in puberty compared to other children of the same chronological age
- Bone growth is delayed
Stimulation testing may be requested for an adult when there are symptoms of GHD and/or hypopituitarism, such as:
- Bone density has decreased
- Deficiencies in lipids, such as excessive cholesterol
- Exercise tolerance is reduced
Other hormone testing, such as thyroid testing, is usually done first to rule out other causes of comparable symptoms. In both children and adults, GH deficiency is uncommon. If GH deficiency was detected in childhood or there is a history of hypothalamic or pituitary illness, it is conceivable in adults.
What does a Growth Hormone blood test check for?
Growth hormone is a hormone that is necessary for children's appropriate growth and development. From birth to adolescence, it promotes correct linear bone growth. Growth hormone regulates the rate at which the body produces energy from meals as well as lipids, proteins, and glucose in both children and adults. It also aids in the regulation of red blood cell formation and muscle mass.
The pituitary gland, a grape-sized gland behind the bridge of the nose at the base of the brain, produces growth hormone. It's released into the bloodstream in pulses throughout the day and night, with maxima occurring largely at night. As a result, a single measurement of GH in blood is difficult to interpret and is rarely relevant in clinical practice. If the sample is collected during a pulse, the value will be higher; if it is taken between pulses, the value will be lower. As a result, GH stimulation and suppression tests are frequently employed to detect GH anomalies.
GH insufficiency is a condition in which the body does not produce enough of
Insufficient GH production causes children to grow more slowly and to be smaller for their age. Some children are born with GH shortage, but others may develop a shortfall later in life as a result of a brain injury or tumor. These disorders can damage the pituitary gland, resulting in a reduction in pituitary function and decreased pituitary hormone production. The cause of a deficit is sometimes unknown.
Growth hormone is involved in the regulation of bone density, muscular mass, and glucose and lipid metabolism in adults. It can also have an impact on the heart and kidneys. Deficiencies might start in childhood or emerge later in life. Damage to the pituitary gland from a head injury, a brain tumor, surgery, or radiation treatment, for example, might create a deficit. Pituitary hormones may be reduced as a result of this. A GH deficit can cause a loss of bone density, muscle mass, and lipid levels to change. Adults with decreased bone density and/or muscle strength, as well as elevated lipids, are not routinely tested for GH insufficiency. These illnesses are caused by GH deficiency, which is a fairly unusual cause.
A GH-secreting pituitary tumor is the most common cause of excessive GH. Surgically removing the pituitary tumor that is producing the excess and/or treating it with medicines or radiation are frequently options. In most situations, GH and IGF-1 levels will revert to normal or near normal levels as a result of this.
In youngsters, too much GH can cause their long bones to continue to develop past puberty, culminating in gigantism, a rare disorder characterized by heights of 7 feet or more. Excess GH can cause face thickness, general weakness, delayed puberty, and headaches in those who have it.
Excess GH in adults can cause acromegaly, an uncommon disorder characterised by bone thickening rather than bone lengthening. Increased GH levels can lead to bigger hands and feet, expanded facial bones, carpal tunnel syndrome, and abnormally enlarged internal organs, despite symptoms like skin thickening, sweating, weariness, headaches, and joint discomfort being modest at first. Skin tags and intestinal polyps can also be caused by too much GH.
If neglected, acromegaly and gigantism can result in type 2 diabetes, a higher risk of high blood pressure, cardiovascular disease, arthritis, and, generally, a shorter lifespan.
Lab tests often ordered with a Growth Hormone test:
- Growth Hormone Releasing Hormone
- Free T3
- Free T4
- IGF BP-3
Conditions where a Growth Hormone test is recommended:
- Pituitary Disorders
- Thyroid Disorders
- Endocrine Syndromes
How does my health care provider use a Growth Hormone test?
Growth hormone testing is frequently done as a follow-up to other aberrant pituitary hormone test results in order to diagnose growth hormone insufficiency and evaluate pituitary gland function.
GH testing is also used to detect excess GH and to diagnose and track acromegaly and gigantism treatment.
Growth hormone is required for appropriate development and growth in children, as well as for the regulation of metabolism in both children and adults. GH is produced by the pituitary gland and released into the blood in pulses throughout the day.
Because growth hormone is released in pulses, a single blood level measurement is rarely useful in clinical practice. As a result, it's common to do tests to see if the pituitary is suppressing or stimulating growth hormone secretion.
GH stimulation tests are used to identify hypopituitarism and GH insufficiency. A sample of blood is collected after 10-12 hours of fasting for a stimulation test. The person is then given an intravenous solution of a chemical that generally stimulates the production of GH from the pituitary under under medical supervision. Blood is obtained at regular intervals and GH levels are measured to evaluate if the pituitary gland was stimulated to produce the desired levels of GH. The most common stimulant is arginine, but clonidine and glucagon are also utilized. Vigorous exercise, which generally induces an increase in GH, could be employed as a GH release stimulant.
GH suppression tests aid in the detection of GH excess. A blood sample is drawn after 10-12 hours of fasting for a suppression test. A standard glucose solution is then given to the person to drink. Blood samples are taken at regular intervals and examined for GH to evaluate if the glucose dose has suppressed the pituitary gland adequately.
Insulin-like growth factor-1 is produced in response to growth hormone. IGF-1 is a hormone that helps promote appropriate bone and tissue growth and development by mediating the effects of GH. Unlike GH, however, its blood level remains constant throughout the day. As a result, IGF-1 is a good indication of average GH levels, and the IGF-1 test is frequently used to diagnose GH shortage or excess.
A GH suppression test and IGF testing can also be used to track how well a GH-producing pituitary tumor is responding to treatment. If a tumor is found, the levels of GH and IGF-1 can be evaluated after it is removed to see if the tumor was completely eliminated. For years following, tests may be required at regular intervals to monitor GH production and detect tumor recurrence.
Prolactin, free T4, TSH, cortisol, FSH, LH, and testosterone are some of the other blood tests that can be used to assess pituitary gland function. These tests are routinely done before GH testing to ensure that they are normal and/or under control with medication before GH testing. Hypothyroidism, for example, must be treated before GH deficiency testing in children; otherwise, a falsely low GH result may be seen.
What do my growth hormone test results mean?
If the person has signs and symptoms of GHD and their GH levels are not significantly stimulated after a GH stimulation test, it is likely that they have a GH deficiency that the health practitioner can treat.
Thyroid issues can induce symptoms similar to GHD, therefore if the person's TSH and/or T4 levels are abnormal, it will likely be addressed first. Hypopituitarism and/or a general decline in pituitary function are also possible. GH deficiency tests should not be done until a person's thyroid function has been assessed. If a child has hypothyroidism, the condition should be addressed and the child's growth rate assessed before GH testing is considered.
If a person engages in rigorous exercise but does not see a rise in GH levels, they may have a GH deficiency. This discovery would need to be followed up with more testing.
We advise having your results reviewed by a licensed medical healthcare professional for proper interpretation of your results.