What Is a Growth Hormone
hormone (GH), also known as human growth hormone (HGH) or somatotropin, is one
of several hormones produced by the pituitary gland in your brain. GH plays a
crucial role in normal human growth and development, especially in children and
adolescents. GH levels that are higher or lower than they should be can lead to
health problems in both children and adults.
A serum growth
hormone test (GH test) is used to measure the amount of GH in your blood. It is
not a routine blood test, since abnormalities of GH are uncommon. If your
doctor has a strong suspicion that you have hormonal abnormalities, they will
use the test to confirm a diagnosis and guide management. Finding any GH
problems can help treatment be more effective.
Limitations of General GH
accurately measure the levels of some hormones in your blood simply by drawing
a sample and analyzing it in the lab. However, GH testing is not so simple.
Finding the level of the hormone at a single point in time doesn’t always help
your doctor make a diagnosis because levels of this hormone naturally rise and
fall throughout the day. This is why more specialized GH tests are usually
will likely order either a growth
hormone suppression test or a growth hormone stimulation test, depending on whether
your doctor suspects that you’re producing too much or too little growth
hormone. Frequently, an insulin-like growth factor-1 test (IGF-1 test) is also
ordered. If you have an excess or a deficiency of GH, you will also have higher
or lower than normal levels of IGF-1. The key advantage of examining IGF is
that, unlike GH, its levels remain stable.
Analyzing GH Levels:
Preparing for and Undergoing Testing
important to follow all preparation instructions. Your doctor may ask you to:
for several hours before the test
a prescription medication a few days prior to the test
before the test
taking medicines that may affect the test results (check with your doctor on
which specific drugs)
itself is fairly routine and carries little discomfort or risk. A healthcare
professional will use a needle to collect one or more blood samples. You may be
asked to drink a solution, or you may be given one through an IV, to see how
your body responds. A lab will process your blood samples to determine whether
your body is producing more or less GH than it should.
Growth Hormone Testing for
may be ordered for children when they show signs of a growth hormone deficiency
(GHD). These include:
growth and bone development
A GHD isn’t
usually the cause for a child’s short stature or slow growth. GHD is rare, and
a child’s below average height can often be attributed to other causes,
including simple genetics inherited from their parents.
may also be performed if there are signs that a child’s body is producing too
much GH. This can result in a very rare condition known as gigantism, in which the long bones do
not stop growing at the end of puberty. People with this condition can grow to
heights of 7 feet or more.
Growth Hormone Testing in
rely on GH to maintain muscle mass and bone density and to regulate the
metabolism of fats. Too little GH can reduce bone density and muscle mass and
disrupt fat levels. However, this is very rare. Extra GH in adults can cause
the bones to thicken, a symptom associated with a condition called acromegaly. Left untreated, acromegaly
can have a number of complications, including a higher risk of arthritis and
Treating Conditions Related
to Growth Hormone Abnormalities
will determine the appropriate course of treatment if testing indicates that
there is a problem with your GH levels. This treatment may involve medication,
surgery, radiation, or a combination of these approaches. Synthetic growth
hormone is often prescribed to those with growth hormone deficiencies.
of your age or the nature of your GH abnormality, early detection is very
important to increase your chances of a good outcome.