What is the Origin of IGF-1 Test?

The test is named after the molecule it quantifies, Insulin-like Growth Factor 1, which was initially recognized for its insulin-mimicking properties and its role in mediating the growth-promoting effects of Growth Hormone. The use of IGF-1 as a clinical test is based on its relatively long half-life and non-pulsatile secretion pattern, which provides a more stable, integrated measure of GH status compared to direct GH measurement.

What is the Mechanism of IGF-1 Test?

Growth Hormone, released in pulses from the pituitary somatotrophs, travels to the liver and stimulates the hepatocytes to synthesize and secrete IGF-1. Once released, IGF-1 circulates, primarily bound to binding proteins, and acts on target tissues via the IGF-1 receptor to promote cellular proliferation, differentiation, and tissue growth. The IGF-1 Test quantifies the total circulating IGF-1, reflecting the integrated GH signaling, which is essential for somatic growth and metabolic regulation throughout life.

IGF-1 Test

Meaning

A clinical blood test that measures the circulating concentration of Insulin-like Growth Factor 1, a key anabolic peptide hormone primarily produced by the liver in response to Growth Hormone (GH) stimulation. The IGF-1 Test serves as the most reliable and stable clinical indicator of average GH secretion over the preceding 24 hours, unlike the pulsatile GH itself. This test is routinely utilized in endocrinology to screen for and monitor disorders of the GH/IGF-1 axis, such as GH deficiency or acromegaly.