Growth Hormone, Serum
Diagnosis of acromegaly and assessment of treatment efficacy (in conjunction with glucose suppression test)
Diagnosis of human growth hormone deficiency (in conjunction with growth hormone stimulation test)
Clinical Information Discusses physiology, pathophysiology, and general clinical aspects, as they relate to a laboratory test
The anterior pituitary secretes human growth hormone (hGH) in response to exercise, deep sleep, hypoglycemia, and protein ingestion. hGH stimulates hepatic insulin-like growth factor-1 and mobilizes fatty acids from fat deposits to the liver. Hyposecretion of hGH causes dwarfism in children. Hypersecretion causes gigantism in children or acromegaly in adults.
Because hGH levels in normal and diseased populations overlap, hGH suppression and stimulation tests are needed to evaluate conditions of hGH excess and deficiency; random hGH levels are inadequate.
Reference Values Describes reference intervals and additional information for interpretation of test results. May include intervals based on age and sex when appropriate. Intervals are Mayo-derived, unless otherwise designated. If an interpretive report is provided, the reference value field will state this.
Males: 0.01-0.97 ng/mL
Females: 0.01-3.61 ng/mL
Reference intervals have not been formally verified in-house for pediatric and adolescent patients. The published literature indicates that reference intervals for adult, pediatric, and adolescent patients are comparable.
Acromegaly: Glucose normally suppresses human growth hormone (hGH) (<1-2 ng/mL). Individuals with acromegaly show no decrease or a paradoxical increase in hGH level. After successful treatment, a normal response to glucose is observed, although hGH levels may not fall to within normal limits.
Deficiency: Low levels, particularly under stimulation, indicate hGH deficiency.
Cautions Discusses conditions that may cause diagnostic confusion, including improper specimen collection and handling, inappropriate test selection, and interfering substances
The test has limited value in assessing growth hormone secretion in normal children. IGF1/15867 Insulin-Like Growth Factor 1, Serum is recommended as the first test for assessing deficient or excess growth during childhood and adolescent development; reference intervals for Tanner stages are available. Suspected causes of dwarfism need to be diagnosed with the aid of provocative testing.
This test is not useful as a screen for acromegaly; IGF1/15867 Insulin-Like Growth Factor 1, Serum is preferred. Elevated levels of human growth hormone indicate the possibility of gigantism or acromegaly, but must be confirmed with stimulation and suppression testing.
Growth hormone is secreted in surges; single measurements are of limited diagnostic value.
Clinical Reference Provides recommendations for further in-depth reading of a clinical nature
1. Camacho-Hubner C: Assessment of growth hormone status in acromegaly: what biochemical markers to measure and how? Growth Hormone IGF Res 2000;10 Suppl B:S125-299
2. Nilsson AG: Effects of growth hormone replacement therapy on bone markers and bone mineral density in growth hormone-deficient adults. Horm Res 2000;54 Suppl 1:52-57
3. Strasburger CJ, Dattani MT: New growth hormone assays: potential benefits. Acta Paediatr 1997 Nov;Suppl 423:5-11
4. Okada S, Kopchick JJ: Biological effects of growth hormone and its antagonist. Trends Mol Med 2001Mar;7:126-132
5. Veldhuis JD, Iranmanesh A: Physiological regulation of human growth hormone (GH)-insulin-like growth factor type I (IGF-I) axis: predominant impact of age, obesity, gonadal function, and sleep. Sleep 1996;19:S221-224