Quick Facts
- Sample: Blood
- Fasting: No fasting required. Stop biotin consumption at least 72 hours prior to the collection.
- Turnaround: 6-8 days. May take longer based on weather, holiday or lab delays.
What This Test Measures
The Insulin-like Growth Factor (IGF-1) Blood Test measures IGF-1, a polypeptide hormone made in the liver and skeletal muscles in response to human growth hormone (HGH) stimulation. IGF-1 mediates the actions of HGH and mirrors an excess or deficiency of it. It is also known as SM-C/IGF-1, Somatomedin-C, and Sulfation Factor.
This test measures IGF-1 itself, not HGH. Unlike HGH, IGF-1 levels are stable throughout the day, so IGF-1 is a useful indicator of average HGH levels. Some labs also report a Z-score, which is not included with LabCorp. This test does not diagnose HGH deficiency.
Note: The Z-score component is not included with LabCorp.
Benefits
- Measures IGF-1, a hormone that mirrors growth hormone activity.
- IGF-1 stays stable through the day, unlike growth hormone.
- Helps your provider evaluate pituitary function and growth hormone-related concerns.
- Supports monitoring for people receiving HGH therapy.
- No fasting required.
- Convenient, low-cost option for patients without insurance.
Who Is This Test For?
- Adults with symptoms of too little or too much growth hormone activity.
- Adults with decreased bone density or muscle strength.
- People whose provider suspects an underactive pituitary gland.
- People receiving HGH therapy who want to monitor their levels.
- People adding context alongside the HGH Serum Test.
- Patients without insurance who want a low-cost alternative to an office visit.
How It Works
- Order Your Test Online
- Visit a Local Lab
- Get Results Online
FAQ
1. What is the purpose of this hormone test?
This test measures IGF-1, a hormone produced in the liver and skeletal muscles in response to HGH stimulation. Because IGF-1 mirrors an excess or deficiency of HGH, it may help your healthcare provider evaluate growth abnormalities and pituitary function, or monitor people on HGH therapy. It does not diagnose HGH deficiency on its own.
2. Who should consider this test?
This test may be helpful for adults with symptoms of too little or too much growth hormone activity, including decreased bone density or muscle strength, or for people whose provider suspects an underactive pituitary gland. It may also be useful for people receiving HGH therapy who want to monitor their levels. This test does not replace a medical evaluation or provide a complete endocrine assessment.
3. How does this test differ from other hormone tests?
Unlike a direct HGH test, this test measures IGF-1 rather than HGH itself. Because IGF-1 levels stay stable throughout the day, it serves as a useful indicator of average HGH levels, while a direct HGH measurement can vary. The two tests are not interchangeable, and this test does not diagnose HGH deficiency on its own. Some labs include a Z-score with this test, but LabCorp does not.
4. Do I need to fast before this test?
No fasting required. Stop biotin consumption at least 72 hours prior to the collection.
5. How quickly will I get results?
6-8 days. May take longer based on weather, holiday or lab delays.
6. How do I interpret the results?
The meaning of your IGF-1 result depends on your symptoms, medical history, and other lab results. It also depends on whether you are receiving HGH therapy. IGF-1 results are often reviewed alongside other clinical information. One abnormal result does not confirm a condition, and one normal result does not rule one out. Your healthcare provider can explain what your result means for you.
Disclaimer: Reference ranges may vary by laboratory. Listed ranges are general guidelines and may differ from those used by the performing lab. Always consult your healthcare provider for interpretation.
7. What should I do if my results are abnormal?
Review your results with a qualified healthcare provider, who can consider your symptoms and history to decide whether further evaluation is appropriate. Do not start, stop, or change any medication or supplement without guidance from your healthcare provider.
8. How often should I get tested?
Testing frequency depends on why you are testing. If you are using this test to monitor HGH therapy or follow up on a concern, test as directed by your healthcare provider. More frequent testing is not always better, so talk with your provider about what makes sense for you.
Pre-test preparation
No fasting required. Stop biotin consumption at least 72 hours prior to the collection.
