Skip to content

Insulin-like Growth Factor I (IGF-I) Serum Concentration

Published: August 9, 2026Updated: August 16, 2026

This test measures the amount of IGF-I, a hormone produced by the liver in response to growth hormone, which plays a key role in growth, cell repair, and metabolism.

Quick summary

["IGF-I helps regulate growth and development; levels can reflect overall health and hormonal balance."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
29775-4
Short code
IGF-I SerPl-sCnc
Synonyms
IGF-I SerPl-sCnc
Category
hormone
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Might Be Ordered

Your doctor may recommend this test if you have concerns about growth issues in children, symptoms of growth hormone deficiency, or conditions affecting metabolism and bone health. It may also be used in monitoring certain cancers or metabolic disorders.

What to Expect Before the Test

No special preparation is usually needed. You may be asked to fast for 8–12 hours before the test if your doctor specifies it, but this is not always required. Bring any medications you’re taking to your appointment.

How the Test Is Performed

A blood sample is drawn from a vein, typically in your arm. The sample is sent to a lab to measure IGF-I levels using a specialized immunoassay method.

What the Results Mean

Results are compared to reference ranges for your age and sex. Low levels may suggest growth hormone deficiency, while high levels could indicate overproduction or certain medical conditions.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

IGF-I Level

Frequently asked questions

What causes IGF-I levels to be low?
Low IGF-I levels can result from growth hormone deficiency, pituitary tumors, kidney disease, malnutrition, or certain genetic disorders. Chronic illnesses like diabetes or liver disease may also affect IGF-I.
What does it mean if my IGF-I level is high?
High IGF-I levels may be associated with growth hormone-secreting tumors, liver disease, or conditions like acromegaly. They can also occur in response to certain medications or metabolic disorders.
Do IGF-I levels change with age?
Yes, IGF-I levels naturally decline with age, especially after puberty. Children and adolescents typically have higher levels, while adults may see gradual decreases, particularly in older adults.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy