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Growth hormone 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:
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:
How it Feels:
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 .
Risks:
- 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 this Test is Performed:
The growth hormone may be measured when there is abnormal growth of a person.
The growth hormone is a protein hormone released from the anterior pituitary gland. In children, the major function of the growth hormone is to stimulate growth. Actually, the major regulator of body growth is IGF-I which is a growth factor released from the liver after being stimulated by growth hormone. In adults, the growth hormone stimulates protein synthesis in muscle and the release of fatty acids from adipose tissue. It inhibits uptake of glucose by muscle while stimulating uptake of amino acids ; the amino acids are used in the synthesis of proteins , and the muscle shifts to using fatty acids as a source of energy.
Normal Values:
The normal range is 0 to 3 ng/ml.
Note: ng/ml = nanograms per milliliter
Abnormal Results:
Greater-than-normal levels may indicate Failure to respond to growth hormone stimulation may be seen with:
Cost:
The estimated cost is $48.
Special Considerations:
Growth hormone levels vary during the day, being highest in the evening. Growth hormone levels decrease with age. Growth hormone levels may be increased with vigorous exercise or in the presence of hypoglycemia .
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.
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