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Test Code LAB12513 Growth Hormone, Serum

Reporting Name

Growth Hormone, S

Useful For

Diagnosis of acromegaly and assessment of treatment efficacy when interpreted in conjunction with results from glucose suppression test

 

Diagnosis of human growth hormone deficiency when interpreted in conjunction with results from growth hormone stimulation test

 

This test is not intended for use as a screen for acromegaly.

 

This test has limited value in assessing growth hormone secretion in normal children.

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type

Serum


Ordering Guidance


For assessing growth hormone secretion in normal children, the recommended test is IGFMS / Insulin-Like Growth Factor 1, Mass Spectrometry, Serum.

 

For acromegaly screening, the preferred test is IGFGP / Insulin-Like Growth Factor 1 and Insulin-Like Growth Factor-Binding Protein 3 Growth Panel, Serum.



Specimen Required


Patient Preparation: For at least 8 hours, patient should be fasting.

Container/Tube:

Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.6 mL

Collection Instructions:

1. If multiple specimens are collected, submit each vial under a separate order.

2. Label specimens appropriately with the corresponding collection times.


Specimen Minimum Volume

0.5 mL

Specimen Stability Information

Specimen Type Temperature Time Special Container
Serum Refrigerated (preferred) 7 days
  Frozen  90 days

Reference Values

Males:

2-<7 years:* 0.05-5.11 ng/mL

7-<12 years:* 0.02-4.76 ng/mL

12-<14 years:* 0.01-6.20 ng/mL

14-<18 years:* 0.02-3.81 ng/mL

≥18 years: 0.01-0.97 ng/mL

 

Females:

2-<7 years:* 0.05-5.11 ng/mL

7-<12 years:* 0.02-4.76 ng/mL

12-<14 years:* 0.01-6.20 ng/mL

14-<18 years:* 0.03-5.22 ng/mL

≥18 years: 0.01-3.61 ng/mL

*Source: Karbasy K, Lin DC, Stoianov A, et al. Pediatric reference value distributions and covariate-stratified reference intervals for 29 endocrine and special chemistry biomarkers on the Beckman Coulter Immunoassay Systems: a CALIPER study of healthy community children. Clin Chem Lab Med. 2016;54(4):643-657. doi:10.1515/cclm-2015-0558

 

Reference intervals for patients younger than 2 years have not been established.

 

For International System of Units (SI) conversion for Reference Values, see www.mayocliniclabs.com/order-tests/si-unit-conversion.html

Day(s) Performed

Monday through Saturday

Test Classification

This test has been cleared, approved, or is exempt by the US Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information

83003

LOINC Code Information

Test ID Test Order Name Order LOINC Value
HGH Growth Hormone, S 2963-7

 

Result ID Test Result Name Result LOINC Value
HGH Growth Hormone, S 2963-7

Clinical Information

The anterior pituitary secretes human growth hormone (hGH) in response to exercise, deep sleep, hypoglycemia, and protein ingestion. hGH stimulates hepatic insulin-like growth factor-1 and mobilizes fatty acids from fat deposits to the liver. Hyposecretion of hGH causes dwarfism in children. Hypersecretion causes gigantism in children or acromegaly in adults.

 

Because hGH levels in normal and diseased populations overlap, hGH suppression and stimulation tests are needed to evaluate conditions of hGH excess and deficiency; random hGH levels are inadequate.

Interpretation

Acromegaly: For suppression testing, normal subjects have a nadir human growth hormone (hGH) concentration below 0.3 ng/mL after ingestion of a 75-gram glucose dose. Patients with acromegaly fail to show normal suppression. Using the Access ultrasensitive hGH assay, a cutoff of 0.53 ng/mL for nadir hGH was found to differentiate patients most accurately with acromegaly in remission from active disease with a sensitivity of 97% (95% CI, 83%-100%) and a specificity of 100% (95% CI, 82%-100%).(1)

 

Deficiency: A normal response following stimulation tests is a peak hGH concentration above 5 ng/mL in children and above 4 ng/mL in adults. For children, some experts consider hGH values between 5 ng/mL and 8 ng/mL equivocal and only GH peak values greater than 8 ng/mL as truly normal. Low levels, particularly under stimulation, indicate hGH deficiency.

Method Description

The instrument used is the Beckman Coulter UniCel DXI 800. The Access ultrasensitive human growth hormone (hGH) assay is a simultaneous one-step immunoenzymatic ("sandwich") assay. A sample is added to a reaction vessel along with polyclonal goat anti-hGH alkaline phosphatase conjugate and paramagnetic particles coated with mouse monoclonal anti-hGH antibody. The patient sample hGH binds to the monoclonal anti-hGH on the solid phase, while the goat anti-hGH-alkaline phosphatase conjugate reacts with a different antigenic site on patient sample hGH. After incubation in a reaction vessel, materials bound to the solid phase are held in a magnetic field while unbound materials are washed away. Then, the chemiluminescent substrate Lumi-Phos 530 is added to the vessel, and light generated by the reaction is measured with a luminometer. The light production is directly proportional to the concentration of hGH in the sample. The amount of analyte in the sample is determined from a stored, multi-point calibration curve.(Package insert: Access Ultrasensitive hGH Growth Hormone. Beckman Coulter Inc.; 05/2020)

Report Available

1 to 3 days

Reject Due To

Gross hemolysis Reject
Gross lipemia OK

Method Name

Immunoenzymatic Assay

Forms

If not ordering electronically, complete, print, and send an Oncology Test Request (T729) with the specimen.

Secondary ID

8688