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Test Name:
Insulin-Like Growth Factor I
- SBMF No:
30053 - Performance Lab Name:
Manual Lab - Test Mnemonic:
IGF-1 - ABN:
Not required - CPT Code:
84305 - LOINC Code:
32023-4 - Also Known As:
IGF-1
IGF-I
Somatomedin - Spec Type:
Serum - Spec Container:
Gold top (SST) or red top (serum) tube - Alt Spec Type:
Plasma - Alt Spec Container:
Green top (heparin) tube - Pref Vol:
1.0 mL - Min Vol:
0.5 mL - Fasting:
No - Spec Collect:
Routine venipuncture - Spec Process:
Serum sample tubes, clot 30 minutes
Promptly centrifuge 15 minutes
Immediately transfer serum or plasma to separate plastic tube and refrigerate
If sample will not be received at SBMF within 24 hours of collection, freeze - Spec Store Transport:
Refrigerated (24 hours) or frozen (preferred) - Spec Stability:
24 hours refrigerated (2-8°C)
1 year frozen (-20°C)– Do not use frost-free units that undergo repeated freeze/thaw cycles - Spec Reject:
Severely hemolyzed or lipemic sample - Methodology:
Chemiluminescent Immunoassay (ChLIA) - Use:
Used in the diagnosis of growth disorders; measurements of IGF-I are a useful adjunct to assessment of growth hormone (GH) secretion - Clinical Significance:
The insulin-like growth factors (IGFs), also referred to as the somatomedins, are a family of peptides whose serum concentrations are regulated principally by growth hormone (GH) and nutritional intake. In humans, IGF peptides have been identified as IGF-I (Somatomedin-C) and IGF-II. IGF-I has a molecular weight of 7,649 Daltons and PI (Isoelectric Point) of 8.2-8.7. It contains 70 amino acid residues in a single chain with 3 disulfide bridges. It is highly dependent on growth hormone and has potent growth-promoting activity in many systems. In serum or plasma, the IGFs are bound to larger proteins.
In the diagnosis of growth disorders, measurements of IGF-I are a useful adjunct to assessment of growth hormone (GH) secretion. A normal plasma or serum IGF-I concentration is strong evidence against GH deficiency, with exceptions being some GH deficient children with craniopharyngiomas and adults who have a prolactin secreting tumor accompanied with GH deficiency and prolactin excess. A low IGF-I value cannot be taken as proof of GH deficiency and requires additional testing to determine whether GH secretion is subnormal. A low IGF-I in a short child is compatible with GH deficiency, nutritional deficiency, chronic illness and/or hypothyroidism.
Patients with active acromegaly almost uniformly have elevated IGF-I values. IGF-I concentrations seem to correlate with disease significantly better than GH, and may provide an indication of improvement after therapy. Currently, the most readily apparent use for serum measurements of IGF-I are for the determination of GH deficiency or GH excess. Another potential use includes the assessment of change in nutritional status. Investigators should find the test useful in studying the effects of disease in serum concentrations of this peptide.
- Reference Range:
Age ng/mL | Age ng/mL Up to 7 days
7 - 15 days
15 days - 1 year
1 - 2 years
2 - 3 years
3 - 4 years
4 - 5 years
5 - 6 years
6 - 7 years
7 - 8 years
8 - 9 years
9 - 10 years
10 - 11 years
11 - 12 years
12 - 13 years
13 - 14 years
14 - 15 years
15 - 16 years0-26
0-41
55-327
51-303
49-289
49-283
50-286
52-297
57-316
64-345
74-388
88-452
111-551
143-693
183-850
220-972
237-996
226-903|
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|16 - 17 years
17 - 18 years
18 - 19 years
19 - 20 years
20 - 25 years
25 - 30 years
30 - 35 years
35 - 40 years
40 - 45 years
45 - 50 years
50 - 55 years
55 - 60 years
60 - 65 years
65 - 70 years
70 - 75 years
75 - 80 years
80 - 85 years
193-731
163-584
141-483
127-424
116-358
117-329
115-307
109-284
101-267
94-252
87-238
81-225
75-212
69-200
64-188
59-177
55-166
IGF-1 (ng/mL) Tanner Puberty
Stages
------
I
II
III
IV
VFemales
--------
128-470
186-695
292-883
394-920
308-1138Males
------
109-485
174-512
230-818
396-776
402-839 - Day Run:
Thu - Time Run:
8:00 am - Time Reported:
5:00 pm - Test Type:
HORMONE
