Insulin Like Growth Factor 1 Test

The test for insulin-like growth factor-1 (IGF-1) is also known as Somatomedin C. It may be used to detect growth hormone (GH) deficiency. The test measures the level of insulin-like growth factor-1 in the blood. IGF-1 is a hormone which along with growth hormone helps promote normal bone and tissue growth and development. The hormone plays a significant role in childhood growth and has anabolic effects in adults. The IGF-1 levels are associated with the level of GH in the body, so the test can be used to diagnose many problems linked to too much or too little GH.

It is recommended that you wear a sleeveless or short-sleeved shirt or a full-sleeved shirt with sleeves rolled up to enable easy withdrawal of blood from your arm. No test preparation is required. However, fasting for at least 12 hours may be required as other tests may be performed along with this test. Certain medications that you are currently taking may affect the test results. So, make sure to inform your doctor regarding all the medications, vitamins, herbs and supplements you are taking. In case the blood withdrawn is to be used for further tests, your doctor will inform you the necessary preparations in prior.

The test is done when your doctor suspects that you may be at a risk of GH-related disease including, Acromegaly which is due to overproduction of growth hormone leading to abnormal growth of hands, feet and facial bones in adults. Laron syndrome in which the GH functions abnormally. It is also used to evaluate pituitary function. The IGF-1 test may be ordered with other pituitary hormone tests like prolactin, FSH or LH to help in diagnosis of pituitary dysfunction. Measurement of IGF-1 and GH also provides information related to GH sensitivity. Elevated levels of IGF-1 indicate increased production of GH. Decreased levels indicate GH deficiency.

A few millilitres of blood sample is required for this test. This will be obtained directly from your arm. The insertion site is prepared for the withdrawal of blood. An elastic band is wrapped around your arm to make the veins swell with blood. The site to be injected is cleansed with antiseptic. The needle is inserted into the vein and a tube attached to the needle is then filled up with blood. A gauze pad or cotton ball is placed over the punctured area as the needle is removed. The sample is transferred to the laboratory for further examination.