Insulin-like growth factor 1 (IGF-1)
Biochemistry Overview / Directory
Purpose of the test
Insulin-like growth factor I (IGF-1) is one of a group of peptides including IGF-2 and IGF binding proteins, whose principal role is to coordinate growth and metabolism. IGF-I is highly dependent on growth hormone and has potent growth promoting activity. It is primarily synthesized in the liver, and then transported in plasma by IGF-binding proteins such as IGFBP-2 and IGFBP-3, These binding proteins are responsible for the relatively high concentration of IGF-1 in plasma and act to minimize plasma concentration fluctuations.
IGF-1 measurements are useful in the diagnosis of growth disorders as an adjunct to assessment of growth hormone secretion. Patients with active acromegaly consistently have elevated IGF-1 concentrations. Serum IGF-1 also seems to correlate with disease status significantly better than growth hormone and may therefore be a superior means to indicate improvement following therapy.
In addition, IGF-1 measurement is useful in the investigation of short stature in children. If measured in conjunction with growth hormone during a stimulation test, it may assist in establishing the cause of retarded growth. A low IGF-1 value cannot be taken as proof of growth hormone deficiency since it is also compatible with nutritional deficiency, chronic illness and hypothyroidism.
Reference Range
Paediatric (Age & Ref Range in ug/L)
1 yr: 55-327
2 yr: 51-303
3 yr: 49-289
4 yr: 49-283
5 yr: 50-286
6 yr: 52-297
7 yr: 57-316
8 yr: 64-345
9 yr: 74-388
10 yr: 88-452
11 yr: 111-551
12 yr: 143-693
13 yr: 183-850
14 yr: 220-972
15 yr: 237-996
16 yr: 226-903
17 yr: 193-731
18 yr: 163-584
19 yr: 141-483
20 yr: 127-424
Adult (Age & Ref Range in ug/L)
21-25 yr: 116-358
26-30 yr: 117-329
31-35 yr: 115-307
36-40 yr: 109-284
41-45 yr: 101-267
46-50 yr: 94-252
51-55 yr: 87-238
56-60 yr: 81-225
61-65 yr: 75-212
66-70 yr: 69-200
71-75 yr: 64-188
76-80 yr: 59-177
81-85 yr: 55-166
Sample Requirements
Serum from a plain vacutainer (330µL).
Storage and Transport
Send frozen on dry ice.
Turnaround Time
1 week
Price
Price available on application - please contact adrian.turner@kch.nhs.uk. Discounts could be available for significant workloads.
Contacts
Dr Roy Sherwood
T 020 3299 3726
Miss Rachel Langworthy
T 020 3299 4130
