What is this test?
IGF-1 is a protein produced mainly by the liver in response to growth hormone. It reflects average growth-hormone activity more reliably than a single hGH measurement.
Why might it be ordered?
- When assessing too slow or accelerated growth in children.
- When growth hormone deficiency or excess is suspected, and to monitor treatment.
What sample is needed?
A healthcare professional collects a venous blood sample. Depending on the method, the laboratory uses serum or plasma.
How should you prepare?
Tell the laboratory about all medicines, hormone treatments, vitamins and supplements you take. Do not stop or change treatment unless your clinician tells you to. Follow any instructions about fasting and the time of collection.
How should you understand the result?
The result is compared with age and gender limits. Nutritional status, liver and kidney disease can also change it. Your result is interpreted using the reference interval on the laboratory report and in the context of your symptoms, medical history and other test findings.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.