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Insulin-like Growth Factor 1; IGF-1

Diagnosis and monitoring of growth disorders.

Pseudonyms: Somatomedin C

General information:

Collection container: Serum with gel separator (Sarstedt brown top, 4.9mL adults/1.1 mL paediatrics) or Serum (Sarstedt white top, 1.2 mL paediatrics only)

Type and volume of sample: 1.0 mL whole blood is required as a minimum volume.

Specimen transport/special precautions: The tubes should be thoroughly mixed before transport to the lab.

Laboratory information: Method Principle.IGF-1 is analysed on an automated instrument using a chemiluminescent immunoassay.

Biological reference ranges:

Male reference range Female reference range
Age (years) Number per group IGF-I (μg/L) Age (years) Number per group IGF-I (μg/L)
<1 year 149 13-138 <1 year 137 16-143
1 15 18-176 1 31 19-160
2 26 23-212 2 28 22-178
3 25 28-247 3 44 25-198
4 29 34-282 4 54 29-219
5 33 40-316 5 89 34-244
6 40 46-349 6 104 39-271
7 38 53-382 7 120 45-302
8 47 60-414 8 160 52-336
9 35 68-443 9 165 59-371
10 40 75-469 10 137 67-407
11 63 83-490 11 99 75-440
12 55 90-505 12 79 82-467
13 88 96-514 13 60 89-488
14 96 101-516 14 54 94-501
15 91 104-512 15 53 98-505
16 94 107-502 16 57 101-502
17 85 109-488 17 27 102-493
18-20 24 109-472 18 28 103-478

 

 

IGF-1 reference ranges - Tanner stage

Percentiles for IGF-I according to Tanner stages based on the Danish cohort (n=854)

- IGF-I ng/mL
Tanner Age range (y) 2.5% 25% 50% 75% 97.5%
Males
I 6.1-12.9 81.3 132.5 160.0 187.9 255.3
II 8.1-14.8 106.2 212.4 276.9 331.8 432.3
III 10.9-16.0 244.9 341.2 407.2 449.0 511.4
IV 12.4-17.1 222.6 364.5 439.0 492.4 577.7
V 13.5-20.0 227.4 308.6 355.7 412.3 517.8
Females
I 5.8-12.1 85.9 152.6 187.7 235.3 323.0
II 9.3-14.1 117.5 190.0 247.3 323.2 451.3
III 9.3-15.1 258.3 335.5 382.8 430.8 528.5
IV 11.8-16.6 224.2 339.8 378.3 437.5 585.8
V 12.5-19.9 188.2 277.4 339.1 394.9 511.6

 

 

Estimated percentiles (2.5%, 25%, 50%, 75% AND 97.5%) derived by Harrell-Davis estimate of quantiles are provided.

Source: J Clin Endocrinol Metab, May 2014, 99(5):1712-1721

Turnaround time: 2 weeks

Clinical information

Insulin-like growth factor-1 is a polypeptide containing 70 amino acids and is one of a number of insulin-like growth factors present in the circulation.

The synthesis of Insulin-like Growth Factor (IGF-1) is stimulated by growth hormone and nutritional intake. IGF-1 levels are very low at birth, rise gradually during childhood, and reach a peak during mid-puberty before beginning to decline again at 40 years.

Almost all IGF-1 circulates bound to specific IGF binding proteins with the major protein being BP3.

IGF-1 measurement is of recognised value in children with growth disorders and in the diagnosis and monitoring of acromegaly.

Factors known to significantly affect the results: Grossly haemolysed samples are unsuitable for analysis

 

(Last reviewed 29th February 2016)