Growth Hormone, 45 Minutes
Also known as: GH 45
Use
The Growth Hormone, 45 Minutes test is a quantitative assay used to evaluate growth hormone (GH) concentrations in patients. In pediatric patients, very low peak GH concentrations on stimulation testing may indicate severe GH deficiency (GHD), while in adults, expected peak GH concentrations depend on the specific stimulation test performed. Additionally, suppression testing can reveal abnormal results in patients with acromegaly.
Special Instructions
The test is standardized to the Recombinant Second International Standard (IS): 98/574. It's important to note that growth hormone results now read approximately 25% lower than previous standards, and reference ranges have been adjusted accordingly.
Limitations
Thresholds distinguishing normal from partial GHD in pediatric patients have not been well established. To diagnose GHD, an inadequate response to two different provocative tests is required. For suppression testing, patients with acromegaly may not show normal suppression compared to healthy subjects.
New York Approved
Methodology
Immunoassay (CLIA)
Biomarkers
LOINC Codes
- 56499-7
Result Turnaround Time
1-2 days
Related Documents
For more information, please review the documents below
Specimen
Plasma
Volume
1 mL per timed specimen
Minimum Volume
0.4 mL per timed specimen
Container
Plasma separator tube or serum separator tube, also acceptable: Green (sodium or lithium heparin), lavender (EDTA), or pink (K2EDTA)
Collection Instructions
Allow specimen to clot completely at room temperature. Separate serum or plasma from cells ASAP or within 2 hours of collection. Transfer to ARUP Standard Transport Tubes.
Storage Instructions
Frozen. Also acceptable: Refrigerated.
Causes for Rejection
Tissue or urine. Grossly hemolyzed or lipemic specimens.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 24 hours |
| Refrigerated | 1 week |
| Frozen | 2 months |