|See Also||Lab Tests|
This test is used to identify GH deficiency in adolescents. Symptoms that are indicative of GH deficiency and warrant testing include short stature, delayed sexual maturity, or other growth deficiencies. This test can also be used to document the diagnosis of GH excess in patients with gigantism or acromegaly. Furthermore, it is used as a screening test for pituitary hypofunction. 
- GH, also known as somatotropin, is secreted by the acidophil cells in the anterior pituitary gland.
- It plays a key role in modulating growth from birth until the end of puberty.
- In the total absence of GH, linear growth occurs at one half to one third of the normal rate.
- GH also plays a role in the control of body anabolism by increasing protein synthesis, increasing the breakdown of fatty acids in adipose tissue, and increasing the blood glucose level.
- Patients are required to be kept on nothing by mouth (NPO) status after midnight the morning after the test. Water is permitted.
- Factors which can cause increased levels
- Stress, Exercise, diet, low blood glucose levels
- Drugs: amphetamines, arginine, dopamine, estrogens, glucagon, histamine, insulin, levodopa, methyldopa, and nicotinic acid
- Factors which can cause decreased levels
- Drugs: corticosteroids and phenothiazines
High levels indicate:
- Major surgery
- Deep-sleep state
Low levels indicate:
- GH deficiency
- Pituitary insufficiency
- Failure to thrive
- Delayed sexual maturity
- Growth hormone (GH) stimulation, Somatomedin C
- Pagana Kathleen D, Pagana Timothy J (2006) Mosby's Manual of Diagnostic and Laboratory Tests, Mosby.