What are the other Names for this Test? (Equivalent Terms)
- GH Blood Test
- hGH Blood Test
- Somatotropic Hormone Blood Test
What is Growth Hormone Blood Test? (Background Information)
- Growth hormone (GH) promotes development from birth to puberty. It is also essential for the maintenance of metabolism, skeletal muscle, and bone tissue throughout one’s life
- The pituitary gland, located at the base of the brain, releases GH in periodic bursts; most GH is released during deep sleep
- The hypothalamus of the brain in turn releases hormones, which control GH release by the pituitary gland. GH-releasing hormone (GH-RH) and GH-inhibiting hormone (GH-IH) stimulate and depress GH secretion, respectively
- The growth hormone affects nearly every cell in the body. It causes cells to increase their protein production and their fatty acid metabolism. The growth-inducing effects of GH are important for adaptation to strenuous demands such as exercise. GH also stimulates the replenishment of tissues during wear and tear, which occurs on a daily basis. GH is especially important during childhood for growth and development
- Problems with the pituitary gland or GH-RH may cause GH underproduction. This results in stunted growth, abnormal fat distribution, and difficulty regulating blood sugar
- Excessive production of GH, caused by tumors or defects in the regulatory mechanisms, may cause excessive growth. The resulting conditions, though similar, differ depending on the stage in life (age of the individual) that a GH overproduction occurred:
- GH overproduction before puberty results in gigantism. This is marked by extreme lengthening of the skeleton, sometimes causing heights in excess of 8 feet
- GH overproduction during adulthood results in acromegaly. Acromegaly is marked by bone thickening, but not lengthening, because the bones have already reached their maximum length
- The Growth Hormone Blood Test measures the levels of growth hormone in blood. It is used to diagnose acromegaly, gigantism, and other disorders of GH production by the pituitary gland
What are the Clinical Indications for performing the Growth Hormone Blood Test?
Following are the clinical indications for performing the Growth Hormone Blood Test:
- Follow-up to an x-ray showing abnormal bone development
- Slow growth in early childhood
- Excessive growth in early childhood
- Disproportionate thickening of the features, particularly the jaw, during adulthood
How is the Specimen Collected for Growth Hormone Blood Test?
Following is the specimen collection process for Growth Hormone Blood Test:
Sample required: Blood
Process of obtaining blood sample in adults:
- A band is wrapped around the arm, 3-4 inches above the collection site (superficial vein that lies within the elbow pit)
- The site is cleaned with 70% alcohol in an outward spiral, away from the zone of needle insertion
- The needle cap is removed and is held in line with the vein, pulling the skin tight
- With a small and quick thrust, the vein is penetrated using the needle
- The required amount of blood sample is collected, by pulling the plunger of the syringe out slowly
- The wrap band is removed, gauze is placed on the collection site, and the needle is removed
- The blood is immediately transferred into the blood container, which has the appropriate preservative/clot activator/anti-coagulant
- The syringe and the needle are disposed into the appropriate “sharp container” for safe and hygienic disposal
Preparation required: No special preparation is needed prior to the test.
What is the Significance of the Growth Hormone Blood Test Result?
The significance of the Growth Hormone Blood Test result is explained:
Increased growth hormone levels may indicate:
- Gigantism, if before the onset of puberty
- Acromegaly, if during adulthood
- Stomach and lung cancer
- Renal failure
Decreased growth hormone levels may indicate:
- Adrenocortical hyperfunction
The laboratory test results are NOT to be interpreted as results of a "stand-alone" test. The test results have to be interpreted after correlating with suitable clinical findings and additional supplemental tests/information. Your healthcare providers will explain the meaning of your tests results, based on the overall clinical scenario.
Additional and Relevant Useful Information:
Certain factors may interfere with the results of the Growth Hormone Blood Test. These include:
- Strenuous exercise
- Eating disorders
Certain medications that you may be currently taking may influence the outcome of the test. Hence, it is important to inform your healthcare provider, the complete list of medications (including any herbal supplements) you are currently taking. This will help the healthcare provider interpret your test results more accurately and avoid unnecessary chances of a misdiagnosis.