GROWTH HORMONE - plasma or serum

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Specimen: 5 mL blood in lithium heparin or plain tube. The patient should be fasting.

Method: Immunoassay.

Reference Interval: Dependent on age and assay method. Consult pathologist.

Application: Pituitary and hypothalamic disorders causing growth abnormalities. Growth hormone as an isolated test is of limited value; dynamic tests are required for proper diagnosis. See GROWTH HORMONE STIMULATION TEST , GROWTH HORMONE SUPPRESSION TEST , IGF-I .

Interpretation: Low levels which are not able to be stimulated to a level achieved by normal subjects occur in pituitary dwarfism in children. High or normal levels which cannot be suppressed are found in gigantism and acromegaly.

Reference: Styne DM. In: Greenspan FS and Baxter JD eds. Basic and Clinical Endocrinology. 4th ed. Prentice Hall 1994.

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