Blood Test: Somatomedin C (IGF-1)

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 Somatomedin C?

Somatomedin (so-muh-toe-MEE-den) C is a protein made mostly in the liver. It helps cells grow and divide in response to stimulation by human growth hormone (hGH), also called somatotropin (STH).

While hGH levels vary throughout the day depending on a person’s diet and activity levels, somatomedin C levels in the blood are more stable. So measuring it is a way for doctors to see how much hGH the is making.

Why Are Somatomedin C Tests Done?

A somatomedin C test helps doctors see if the body is making a normal amount of hGH.

They usually order it to check for pituitary gland disorders and problems with growth hormone production. Symptoms such as short stature or excessive growth (gigantism) may prompt doctors to order a somatomedin C test, also called an insulin-like growth factor-1 (or IGF-1) test.

The test also can check a child's nutrition because malnutrition may lower somatomedin C levels.

What if I Have Questions?

If you have questions about the somatomedin C test or what the results of the test mean, talk to your doctor.