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What Is a Blood Test?

By taking and testing a small sample of a person’s blood, doctors can check for many kinds of diseases and conditions. Blood tests help doctors check how the body’s organs are working and see if medical treatments are helpful.

To help your child get ready for a blood test, find out if they need to fast (not eat or drink) or should stop taking medicines before the test. Explain what to expect during the test. If your child is anxious about it, work together on ways to stay calm.

What Is IGF Binding Protein-3 (IGFBP-3)?

Insulin-like growth factor binding protein 3 (IGFBP-3) is the main carrier of somatomedin C (also called insulin-like growth factor-1, or IGF-1) in the body. Blood levels of both these proteins are controlled by human growth hormone (hGH), a hormone made by the pituitary gland.

IGFBP-3 also helps extend the life of somatomedin C in the blood and helps control its effects on body tissues.

IGFBP-3 levels are highest during childhood and puberty. They decrease during adulthood. Levels also may be affected by sexual maturation and nutritional status.

Why Are IGFBP-3 Tests Done?

The IGFBP-3 test can help doctors see if the body is making a normal amount of human growth hormone. They’ll order it to check for disorders and problems in growth hormone production (for instance, if a child has short stature or excessive growth, known as gigantism). The test also can help them monitor treatment of growth disorders.

What if I Have Questions?

If you have questions about the IGFBP-3 test or what the results of the test mean, talk to your doctor.

Medically reviewed by: Larissa Hirsch, MD
Date reviewed: May 2023