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IGF-1

Insulin-like Growth Factor 1 Somatomedin C
Serum (SST) nmol/L or µg/L

About this test

Produced by the liver in response to GH. Has stable diurnal levels making it a better marker of GH status than random GH. Used to screen for acromegaly and GH deficiency.

Reference Ranges

Sex Age Range Notes
All 18–25 yrs See notes Age-specific reference ranges (peak in puberty; declines with age)
All 25–40 yrs 11.5 – 30 Approximate adult 25–40 range in nmol/L; consult local range
All ≥ 40 yrs 7 – 23 Approximate adult >40; consult local age-specific range

Clinical Interpretation

Low / Decreased
Low IGF-1 — GH deficiency, malnutrition, liver disease, hypothyroidism, poorly controlled diabetes.
High / Increased
Elevated IGF-1 — acromegaly, gigantism. Confirm with GH suppression (OGTT).

Related Tests

Growth Hormone Prolactin
Specimen
Serum (SST)
Reporting Unit
nmol/L or µg/L
Category
⚗️ Endocrinology

⚠ Clinical Note
Reference ranges are indicative. Always interpret results in the context of the individual patient and local laboratory reference intervals, which may vary.