Definition
A test that measures the amount of the growth hormone in blood.

Alternative Names
GH

How the test is performed
Adult or child:
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (fill with blood). A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the tourniquet is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

Infant or young child:
The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

How to prepare for the test
Adults:
There is no special preparation.

Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:

infant test or procedure preparation (birth to 1 year)
toddler test or procedure preparation (1 to 3 years)
preschooler test or procedure preparation (3 to 6 years)
schoolage test or procedure preparation (6 to 12 years)
adolescent test or procedure preparation (12 to 18 years)

How the test will feel
When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

What the risks are
excessive bleeding
fainting or feeling lightheaded
hematoma (blood accumulating under the skin)
infection (a slight risk any time the skin is broken)
multiple punctures to locate veins

Why the test is performed
The growth hormone may be measured when there is abnormal growth in adults and children or when there is a history of a pituitary problem.

The growth hormone is released from the anterior pituitary gland. Pituitary adenomas can produce excess growth hormone. This can cause abnormal growth patterns called acromegaly in adults and gigantism in children. Excess growth hormone can increase blood pressure and blood sugar

Individuals with growth hormone resistance or known pituitary disease may not produce enough growth hormone. In children this can cause short stature. In adults, growth hormone insufficiency can lead to changes in muscle mass, cholesterol levels, and bone strength.

Treatment
Normal Values
The normal range is 0 to 3 ng/ml.
Note: ng/ml = nanograms per milliliter

What abnormal results mean
High levels of growth hormone may indicate
acromegaly
giantism
pituitary tumor
growth hormone resistance

Low levels of growth hormone may indicate:
dwarfism
hypopituitarism

Special considerations
Growth hormone measurements are usually combined with other laboratory tests, such as IGF-1 levels or provocative tests, such as GHRH stimulation tests.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.