Insulin-like Growth Factor 1 (IGF-1), LC/MS

CPT Code: 84305
Order Code: 16293
Synonyms: IGF1, Somatomedin-C, Insulin Like Growth Factor
ABN Requirement: No
Specimen: Serum
Volume:  0.5 mL
Minimum Volume:  0.3 mL
Container: Gel-barrier tube (SST)

Collection:

  1. Collect and label sample according to standard protocols.
  2. Gently invert tube 5 times immediately after draw. DO NOT SHAKE.
  3. Allow blood to clot 30 minutes.
  4. Centrifuge for 10 minutes.

Transport: Store serum at 2°C to 8°C after collection and ship the same day per packaging instructions included with the provided shipping box.
Special Instructions: Collect blood in a red-top or SST vacutainer. For red-top vacutainers, allow blood to clot (10-15 minutes) at room temperature. Separate serum from cells and refrigerate.
Stability:

Ambient (15-25°C): 48 hours
Refrigerated (2-8°C): 7 days
Frozen (-20°C): 60 days

Causes for Rejection: Moderate hemolysis

Methodology: Liquid Chromatography/Mass Spectrometry (LC/MS)

Turn Around Time:  3-6 days

Reference Range(s):

Pediatric Male (ng/mL) Female (ng/mL)
<1 year 14-142 17-185
1-1.9 years 12-134 15-175
2-2.9 years 12-135 16-179
3-3.9 years 30-155 38-214
4-4.9 years 28-181 34-238
5-5.9 years 31-214 37-272
6-6.9 years 38-253 45-316
7-7.9 years 48-298 58-367
8-8.9 years 62-347 76-424
9-9.9 years 80-398 99-483
10-10.9 years 100-449 125-541
11-11.9 years 123-497 152-593
12-12.9 years 146-541 178-636
13-13.9 years 168-576 200-664
14-14.9 years 187-599 214-673
15-15.9 years 201-609 218-659
16-16.9 years 209-602 208-619
17-17.9 years 207-576 185-551

 

Adult ng/mL
18-19.9 years 108-548
20-24.9 years 83-456
25-29.9 years 63-373
30-39.9 years 53-331
40-49.9 years 52-328
50-59.9 years 50-317
60-69.9 years 41-279
70-79.9 years 34-245
>80 years 34-246
Z-Scores -2.0 – +2.0

Clinical Significance: Insulin-like Growth Factor 1 (IGF-1 or Somatomedin C), a protein involved in stimulating somatic growth, is regulated principally by Growth Hormone (GH) and nutritional intake. IGF-1 is transported in serum by several proteins; this helps maintain relatively high IGF-1 plasma levels and minimizes fluctuations in serum IGF-1 concentrations.

Measuring IGF-1 is useful in several growth-related disorders. Dwarfism caused by deficiency of growth hormone (hypopituitarism) results in decreased serum levels of IGF-1, while acromegaly (growth hormone excess) results in elevated levels of IGF-1. IGF-1 measurements are also helpful in assessing nutritional status; levels are reduced in undernutrition and restored with a proper diet.

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