IGF1 (Insulin-like growth factor 1)
Clinical Biochemistry
Background Information
Insulin-like growth factor-1 (IGF-1) in the circulation originates mainly from the liver under control of pituitary growth hormone (GH). Levels of IGF-1 parallel those of GH.
IGF-1 levels are therefore indicated in:
- Diagnosis and treatment monitoring of GH secreting tumours
- Investigation of short stature in children
- Investigation of suspected pituitary insufficiency
Patient Preparation
No specific patient preparation is required.
Sample Requirements
For adults, blood taken into a 5mL gold top tube (or rust top for the Acute Unit)
For children, blood taken into a 3.5mL rust top tube
For neonates, blood taken into a 1mL minicollect plain tube or a 1mL minicollect lithium heparin
Storage/Transport
Do not store. Send at ambient temperature to the laboratory on the day of sample collection.
Required Information
Relevant clinical details including reason for the request.
Turnaround Times
The samples are analysed once a week.
Reference Ranges
| Age (years) | Female (nmol/L) | Male (nmol/L) |
|---|---|---|
| 0 – 2 | 2.2 – 12.8 | 1.6 – 12.5 |
| 3 – 5 | 5.7 – 24.2 | 3.5 – 17.6 |
| 6 – 9 | 10.6 – 40.0 | 8.2 – 30.8 |
| 10 | 14.7 – 52.1 | 11.2 – 44.9 |
| 11 | 16.1 – 55.9 | 12.3 – 51.4 |
| 12 | 17.3 – 59.1 | 13.2 – 56.9 |
| 13 | 18.3 – 61.3 | 14.1 – 61.2 |
| 14 | 19.1 – 62.9 | 15.1 – 64.1 |
| 15 | 19.8 – 63.5 | 15.7 – 65.6 |
| 16 | 20.2 – 63.5 | 16.4 – 65.9 |
| 17 | 20.4 – 62.7 | 16.9 – 64.8 |
| 18 | 20.4 – 61.0 | 17.3 – 62.4 |
| 19 | 20.3 – 58.8 | 17.6 – 59 .0 |
| 20 | 19.9 – 56.2 | 17.8 – 55.2 |
| 21 – 25 | 18.1 – 49.1 | 17.8 – 45.6 |
| 26 – 30 | 15.5 – 39.7 | 16.4 – 35.5 |
| 31 – 35 | 13.6 – 33.4 | 14.9 – 32.4 |
| 36 – 40 | 12.4 – 30.3 | 13.5 – 30.7 |
| 41 – 45 | 11.3 – 29.1 | 12.1 – 29.0 |
| 46 – 50 | 10.3 – 28.6 | 10.8 – 27.4 |
| 51 – 55 | 9.4 – 27.5 | 9.5 – 26.2 |
| 56 – 60 | 8.5 – 25.4 | 8.3 – 25.3 |
| 61 – 65 | 7.6 – 23.1 | 7.7 – 24.6 |
| 66 – 70 | 7.1 – 21.5 | 7.3 – 24.2 |
| 71 and above | 7.0 – 21.0 | 6.9 – 24.1 |
Note: levels of IGF-1 may be low with anorexia or malnutrition.
Further Information
To learn more about IGF-1 visit Lab Tests Online
Page last updated: 05/11/2025 | Page last reviewed: 05/11/2025