Davis's Lab & Diagnostic Tests
Growth Hormone, Stimulation and Suppression Tests
General
Synonym/Acronym:
Somatotropic hormone, somatotropin, GH, hGH.
Rationale
To assess pituitary function and evaluate the amount of secreted growth hormone (GH) to assist in diagnosing diseases such as giantism and dwarfism.
Patient Preparation
The patient should fast and avoid strenuous exercise for 12 hr before specimen collection for stimulation and suppression studies. Some medications may adversely interact with the inducer used for the test, e.g., amphetamine, dextroamphetamine, and methylphenidate interact with clonidine. The requesting HCP should be aware of any potential interacting medications used in the studies and advise restrictions by medical direction. Protocols may vary depending on the type of induction used.
Normal Findings
Method: Immunoassay.
| Age | Conventional Units | SI Units (Conventional Units × 1) |
|---|---|---|
| Cord blood | 8–40 ng/mL | 8–40 mcg/L |
| 1 d | 5–50 ng/mL | 5–50 mcg/L |
| 1 wk | 5–25 ng/mL | 5–25 mcg/L |
| Child | 2–10 ng/mL | 2–10 mcg/L |
| Adult | ||
| Male | 0–5 ng/mL | 0–5 mcg/L |
| Female | 0–10 ng/mL | 0–10 mcg/L |
| Male older than 60 yr | 0–10 ng/mL | 0–10 mcg/L |
| Female older than 60 yr | 0–14 ng/mL | 0–14 mcg/L |
| Stimulation Tests | ||
| Rise above baseline | Greater than 5 ng/mL | Greater than 5 mcg/L |
| Peak response | Greater than 10 ng/mL | Greater than 10 mcg/L |
| Suppression Tests | 0–2 ng/mL | 0–2 mcg/L |
Critical Findings and Potential Interventions
N/A
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