Chemical Pathology

Notes

The insulin-like growth factor IGF-1 circulates bound to proteins. IGFBP-3 is the pre-dominant binding protein, levels of which are growth hormone dependant.

IGFBP-3 is very occasionally requested in addition to IGF-1 by the paediatricians, in the investigation of growth disorders in children.

Sample requirements

For children and neonates, blood taken into a 1mL minicollect plain tube.

A 3.5mL rust top tube can be used in older children but serum must be separated from the gel the same day.

1ml serum tube

Storage/transport

Do not store. Send at ambient temperature to the laboratory on day of sample collection.

Required information

Relevant clinical details, including reason for the request.

Turnaround times

Samples are sent for assay to the Royal Surrey County Hospital, Guildford, with results expected back within two weeks.

Reference ranges

Age Group (years) IGFBP-3 (male) mg/L IGFBP-3 (female) mg/L
Less than 1 year 1.1 - 3.2 1.1 - 3.3
1 1.3 - 3.6 1.2 - 3.7
2 1.5 - 4.1 1.4 - 4.2
3 1.6 - 4.5 1.6 - 4.6
4 1.8 - 4.9 1.7 - 4.9
5 1.9 - 5.2 1.9 - 5.2
6 2.0 - 5.4 1.9 - 5.4
7 2.1 - 5.5 2.0 - 5.5
8 2.2 - 5.6 2.1 - 5.6
9 2.2 - 5.7 2.2 - 5.8
10 2.3 - 5.8 2.3 - 5.9
11 2.4 - 6.0 2.4 - 6.1
12 2.5 - 6.1 2.4 - 6.2
13 2.5 - 6.2 2.5 - 6.3
14 - 15 2.6 - 6.3 2.6 - 6.4
16 2.6 - 6.3 2.7 - 6.5
17 - 18 2.7 - 6.3 2.7 - 6.5
19 2.7 - 6.3 2.8 - 6.5
20 2.7 - 6.4 2.8 - 6.6
21 - 25 2.8 - 6.4 2.9 - 6.6
26 - 30 2.7 - 6.1 2.8 - 6.2
31 - 35 2.6 - 6.0 2.6 - 5.8
36 - 40 2.6 - 6.0 2.5 - 5.7
41 - 45 2.6 - 6.0 2.4 - 5.6
46 - 50 2.4 - 5.9 2.3 - 5.6
51 - 55 2.3 - 5.8 2.3 - 5.7
56 - 60 2.1 - 5.7 2.2 - 5.7
61 - 65 2.0 - 5.6 2.2 - 5.7
66 - 70 1.9 - 5.5 2.1 - 5.6
71 - 75 1.8 - 5.2 2.0 - 5.5
76 - 80 1.7 - 5.0 2.0 - 5.5
81 - 85 1.6 - 5.0 1.9 - 5.5
86 - 90 1.7 - 5.2 2.0 - 5.7