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Test Code LAB525 Human Growth Hormone, Blood

Performing Laboratory

St. Louis Children's Hospital - Chemistry

Specimen Requirements

Patient preparation: Sample should not be taken frmo patients receiving therapy with high biotin doses (i.e. >5 mg/day) until at least 8 hours following the last biotin administration.

Container/Tube  
Preferred: Mint green-top Lithium Heparin (MNTGRN LiHep) tube
Acceptable: Gold SST tube, Plain, red-top tube, or Lavender-top (EDTA) tube
Collection Volume: 1.0 mL (minimum 0.6 mL)

Submission Container/Tube: If specimen is coming from outside facility and collected in a microtainer, plain red-top tube, or lavender-top tube aliquot processed sample into a plastic vial for transport (labeling with specimen type).
Special Instructions:

If multiple specimens are collected, make sure all samples have orders and are labeled with correct collection time.
Send each specimen promptly to lab.

Sample Rejection

Samples that are grossly hemolyzed

Mislabeled or unlabeled speicmens

Logistics

Test Availability: Daily
Cut-off time: None; performed as received
Turnaround Time: Same day; 2 hours from receipt in performing lab

Methodology

Electrochemiluminescence Immunoassay (ECLIA) sandwich principle

Additional Information

FOR SLCH LABORATORY USE ONLY

Lab Processing Instructions: Centrifuge specimen to separate within 1 hour of collection. If specimen is collected in microtainer, plain red-top tube or lavender-top tube aliquot sample into a Roche false-bottom tube for testing (labeling aliquot with specimen type).
Processed Volume: 0.3 plasma/serum

Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed)  Ambient 1 hour
Plasma/Serum (processed) Refrigerated (preferred)    8 hours
  Ambient  1 hour
  Frozen  2 months    

LOINC

in process

Last Reviewed

6/2025

Reference Range

Reference Range: None established.
Values below the limit of detection are reported as <0.03 ng/mL

Due to pulsatile secretion, random measurement has little clinical utility. Stimulatory tests in the assessment of growth hormone deficiency yield concentrations greater than 7.0-10 ng/mL in normal pediatric patients. Growth hormone concentrations are suppressed to less than 1.0 ng/mL in normal patients following glucose load. References: Clin Lab Med 2004;24:141-174, J Clin Endocrinol Metab 2007;92:4623-4629.

Critical Values: None established
 

Limitations:

  • In rare cases, interference due to extremely high titers of antibodies to analyte-specific antibodies, streptavidin or ruthenium can occur.

 For diagnostic purposes, the results obtained from this assay should always be used in combination with the clinical examination, patient medical history, and other findings.

Test Classification and CPT Coding

83003