View Full Version : Somatomedin C Levels?

09-25-2007, 08:05 PM
I just got my bloodwork done and one of the results was my Insulin Like Growth Factor-1 levels.

I was wondering what the normal reference ranges were to Somatomedin C?
Theres no reference ranges listed for this test like the other ones. Ive searched and had no success. Mine was 252 i have no idea what that means.


09-25-2007, 09:56 PM

Hope it helps some.

The Test

How is it used?
When is it ordered?
What does the test result mean?
Is there anything else I should know?

How is it used?
IGF-1 is measured to help diagnose the cause of growth abnormalities and to evaluate pituitary function. IGF-1 levels reflect integrated GH status and, along with GH provocation tests, are used to help diagnose GH deficiency. These tests, while generally ordered in children suspected of GH abnormalities, may also be used in adults with GH deficiency. IGF-1 levels and the measurement of GH also provide information related to GH Insensitivity (GHI).
IGF-1 also may be ordered with other pituitary hormone tests, such as ACTH (Adrenocorticotropic hormone), to help diagnose hypopituitarism. It also may be used to monitor the effectiveness of treatment for growth hormone deficiencies and GHI.

IGF-1 testing and a GH suppression test can be used to detect a GH-producing pituitary tumor. Its presence is then confirmed with imaging scans that help identify and locate the tumor. If surgery is necessary, GH and IGF-1 levels are measured after the tumor’s removal to determine whether or not all of it was successfully removed. Drug and/or radiation therapy may be used in addition to (or sometimes instead of) surgery to try to decrease GH production and return IGF-1 to normal or near normal concentrations. IGF-1 may be used to monitor the effectiveness of this therapy at regular intervals for years afterward to monitor GH production and to detect tumor recurrence.

When is it ordered?
IGF-1 testing may be ordered, along with a GH stimulation test, when a child has symptoms of GH deficiency, such as a slowed growth rate and short stature. They also may be ordered in adults with suspected GH deficiency. An IGF-1 also may be ordered when a doctor suspects that a person has an underactive pituitary gland. In addition, IGF-1 levels are ordered to monitor patients on GH therapy.
IGF-1 testing may be ordered, along with a GH suppression test, when a child has symptoms of gigantism, an adult shows signs of acromegaly, and/or when a doctor suspects that a patient has hyperpituitarism.

When a GH-producing pituitary tumor is found, GH and IGF-1 are ordered after the tumor is surgically removed to determine whether all of the tumor has been extracted. IGF-1 also is ordered at regular intervals when a patient is undergoing the drug and/or radiation therapy that frequently follow tumor surgery.

IGF-1 levels may be ordered at regular intervals for many years to monitor a patient’s GH production and to watch for pituitary tumor recurrence.

What does the test result mean?
NOTE: A standard reference range is not available for this test. Because reference values are dependent on many factors, including patient age, gender, sample population, and test method, numeric test results have different meanings in different labs. Your lab report should include the specific reference range for your test. Lab Tests Online strongly recommends that you discuss your test results with your doctor. For more information on reference ranges, please read Reference Ranges and What They Mean.

If IGF-1 concentrations are decreased, then it is likely that there is a deficiency of GH (GH Deficiency; GHD) or an insensitivity to GH (GH Insensitivity; GHI). If this is in a child, the GH deficiency may have already caused short stature and delayed development and may be treated with GH supplementation. While it is normal for adult levels to be lower than those in children because of an age-related decrease in production, adults also may have low IGF-1 due to GHD or GHI and will need to be treated.
If a decrease in IGF-1 is due to a more general decrease in pituitary function (hypopituitarism), then several of the patient’s pituitary hormones will need to be evaluated and may be supplemented to bring them up to normal levels. Reduced pituitary function may be due to inherited defects or can rise as a result of pituitary damage following conditions such as trauma, infections, and inflammation.

Decreased levels of IGF-1 also may be seen with nutritional deficiencies (including anorexia nervosa), chronic kidney or liver disease, inactive/ineffective forms of GH, and with high doses of estrogen.

Elevated levels of IGF-1 usually indicate an increased production of GH. Since GH levels vary throughout the day, IGF-1 concentrations are a reflection of average GH production, not of the actual amount of GH in the blood. This is accurate up to the point at which the liver’s capacity to create IGF-1 is reached. With severely increased GH production, IGF-1 levels will stabilize at an elevated maximum concentration.

Increased concentrations of GH and IGF-1 are normal during puberty and pregnancy but otherwise are most frequently due to pituitary tumors (usually benign). If other pituitary hormones are also abnormal, then the patient may have a condition causing general hyperpituitarism.

If IGF-1 is still elevated after the surgical removal of a pituitary tumor, then the surgery may not have been fully effective. Decreasing IGF-1 concentrations during subsequent drug and/or radiation therapies indicate that the treatment is lowering GH production. If levels of IGF-1 become “normalized,” then the patient is no longer producing excess amounts of GH. When a patient is undergoing long term monitoring, an increase in IGF-1 levels may indicate a recurrence of the pituitary tumor.

Is there anything else I should know?
IGF-1 testing is being evaluated as part of a sports-related drug abuse screen for GH-related performance-enhancing substances. GH and IGF-1 enhancers (supplements taken by some athletes during the training season to increase muscle mass and strength) have been banned by U.S. and international sports federations. It is difficult to detect increases in IGF-1 related to the use of supplements as opposed to those increases due to rigorous training. Approaches using a combination of GH, IGF-1, IGF-binding proteins, and other biological markers seem promising and could lead to the development of anti-doping tests.

09-25-2007, 11:11 PM
thanks i guess im gonna have to discuss it with my doctor then..... there are no reference ranges on the test result paper i got in the mail.