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Growth Hormone Level

Human growth hormone, hGH, somatotropin, Growth Hormone

Test Codes

Antrim #17034, EPIC: LAB5809, SOFT: GH

Department

Special Chemistry

Instructions

Patient must be fasting and at complete rest for 30 minutes before blood collection.

Specimen Collection Criteria

Collect: One Gold-top SST tube. (Minimum Whole Blood: 2.0 mL)

Physician Office/Draw Specimen Preparation

Let each specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Transfer 1.0 mL serum to a plastic aliquot tube and freeze (-20°C/-4°F or below) immediately. (Minimum Serum: 0.5 mL)

Preparation for Courier Transport

Transport: 1.0 serum in a plastic transport tube, frozen (-20°C/-4°F or below). (Minimum Serum: 0.5 mL)

Rejection Criteria

• Grossly hemolyzed, lipemic or icteric specimens.
• Non-frozen specimens.
• Plasma specimens.
• Specimens not collected and processed as indicated.

In-Lab Processing

Let each specimen clot 30-60 minutes then immediately centrifuge to separate serum from cells. Transfer 1.0 mL serum to a plastic aliquot tube and freeze (-20°C/-4°F or below) immediately. (Minimum Serum: 0.5 mL)

Storage

Specimen Stability for Testing:

Centrifuged SST Tubes and Microtainers^® with Separator Gels
Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Red-top Tubes and Microtainers^® without Separator Gels
Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): Unacceptable
Frozen (-20°C/-4°F or below): Unacceptable

Serum Specimens (Pour-Overs)
Room Temperature (20-26°C or 68-78.8°F): Unacceptable
Refrigerated (2-8°C or 36-46°F): 8 hours
Frozen (-20°C/-4°F or below): 2 months

Specimen Storage in Department Prior to Disposal:

Refrigerated (2-8°C or 36-46°F): 7 days

Laboratory

Royal Oak Special Testing Laboratory.

Performed

Monday - Friday. 
Results available within 2 business days.

Reference Range

Adults
Males: 0.1-3.0 ng/mL.
Females: 0.1-8.0 ng/mL.

Reference range not established for children less than 19 years of age.

Test Methodology

Chemiluminescent Immunoassay.

Interpretation

Caution must be exercised in the clinical interpretation of growth hormone levels. These vary throughout the day, making it difficult to define a reference range or to judge an individual's status based on single determinations. Many factors are known to influence the rate of growth hormone secretion, including periods of sleep and wakefulness, exercise, stress, hypoglycemia, estrogens, corticosteroids, L-dopa, and others. Challenge/stimulation tests (e.g., arginine, GHRH, insulin, L-dopa) may be used to investigate individuals suspected of having GH deficiency.

Clinical Utility

The measurement of human growth hormone (hGH) aids in the diagnosis and management of various forms of inappropriate growth hormone secretion. Clinical disorders of hyposecretion include dwarfism and unattained growth potential. Hypersecretion is associated with giantism and acromegaly.

CPT Codes

83003
LOINC: 2963-7, 30 Minutes 15347-8, 60 Minutes 14146-5, 90 Minutes 14147-3

Contacts

Last Updated

1/11/2023