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Test Code LAB526 Insulin-Like Growth Factor 1 (IGF1), Blood

Performing Laboratory

St. Louis Children's Hospital Laboratory - Chemistry

Specimen Requirements

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

Collection Container/Tube:

Preferred: Mint green-top Lithium Heparin (MNTGRN LiHep) tube

Acceptable: Plain red-top tube, Gold SST gel tube, or Lavender-top (EDTA) tube

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

Specimen Collection Volume: 2.0 mL (minimum 0.6 mL)

Special Instructions: Send to lab promptly

 

Sample Rejection

Mislabled or unlabeled specimens

Specimens that are grossly hemolyzed

 

Logistics

Test Availability: Monday-Sunday

Cut-off time: None, performed as received

Turnaround Time: Same Day; 2 hours from receipt in performing lab

Reference Values

Reference Interval: 

Age: years                   Male                              Females                 
<2  10-200 10-200
2-3 10-250 10-250
3-4 20-250 20-250
4-5 30-250 30-250
5-6 40-250 40-250
6-7 50-275 45-250
7-8 50-300 45-300
8-9 60-350 50-350
9-10 70-400 60-400
10-11 70-450 70-500
11-12 80-500 90-600
12-13 85-550 100-650
13-14 90-600 110-700
14-15 95-620 115-750
15-16 100-650 120-700
16-17 100-650 120-600
17-18 100-600 120-500
18-20 90-500 100-400
For reference intervals for patients ≥20 years call the lab at 314-454-4268 if needed
Tanner stages    Male                  Female          
I 80-250 80-320
II 100-450 120-450
III 250-500 250-550
IV 225-600 225-600
V 225-500 180-500

Assay calibrated to WHO 02/254 and instituted at SLCH 5/2018.

Current interpretive criteria established 5-10-2018.

References:

  1. Elecsys IGF-1 Package Insert 2017-10, V 1.0

  2. Mayo Medical Laboratories IGFMS entry (https://www.mayomedicallaboratories.com/test-catalog/Overview/62750) accessed 5-9-2018.

  3. Bidlingmaier M, Fredrich N Emen RT et al.  J Clin Endocrinol Metab 2014;99:1712-1721

 

Critical Value: None established

 

Methodology

Sandwich principle

Limitations

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

Additional Information

FOR SLCH CORE LABORATORY USE ONLY

Lab Processing Instructions: Centrifuge to separate. If specimen is collected in a 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: 0.5 mL (minimum 0.3 mL) plasma/serum

Analyte Stability:

Specimen Type Temperature Time
Whole Blood (unprocessed)  Ambient 8 hours
Plasma/Serum (processed) Refrigerated (preferred) 48 hours
  Ambient  24 hours
  Frozen  28 days        

Test Classification and CPT Code

84305

LOINC

in process

Last Reviewed

06/2025