Growth Hormone, 120 Minutes
Also known as: GH 120
Use
The Growth Hormone, 120 Minutes test is crucial in diagnosing and managing growth hormone-related disorders, such as growth hormone deficiency (GHD) and acromegaly. For pediatric patients, very low peak growth hormone concentrations on stimulation testing indicate severe GHD, though thresholds distinguishing normal from partial GHD are not well established. In adults, expected peak GH concentrations depend on the stimulation test performed, based on guidelines by the Endocrine Society. For suppression testing, healthy individuals should exhibit GH levels below 1 ng/mL within 2 hours of glucose ingestion, while patients with acromegaly will not show the expected suppression.
Special Instructions
Ensure that the specimen is allowed to clot completely at room temperature and separate serum or plasma from cells as soon as possible, or within 2 hours of collection. Transfer 1 mL of serum or plasma per timed specimen to individual ARUP Standard Transport Tubes.
Limitations
Thresholds distinguishing normal from partial growth hormone deficiency have not been well established. An inadequate response to two different provocative tests is required for a definitive diagnosis of GHD. Reference ranges have been modified according to the assay manufacturer due to standardization with the Recombinant Second International Standard (IS).
FDA ApprovedNew York Approved
Methodology
Immunoassay (CLIA)
Biomarkers
LOINC Codes
- 14144-0
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL
Minimum Volume
0.4 mL
Container
ARUP Standard Transport Tube
Collection Instructions
Collect plasma separator tube or serum separator tube for each timed specimen. Green (sodium or lithium heparin), lavender (EDTA), or pink (K2EDTA) tubes are acceptable. Separate serum or plasma from cells within 2 hours.
Storage Instructions
Frozen, but refrigeration is also acceptable
Causes for Rejection
Tissue, urine, and grossly hemolyzed or lipemic specimens are unacceptable.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 1 week |
| Frozen | 2 months |