Insulin-Like Growth Factor 1 (IGF-1)
Insulin-Like Growth Factor 1 (IGF-1) is a hormone-related blood marker that reflects the body’s growth signaling over time. IGF-1 on a lab report is often used to summarize how much of this marker is circulating in the blood, and the result is commonly reviewed with age- and sex-based ranges. On a blood test, high IGF-1 or low IGF-1 can reflect differences in production, binding, or natural variation.
What Is Insulin-Like Growth Factor 1 (IGF-1)?
Insulin-Like Growth Factor 1 (IGF-1) is a hormone-related blood marker that reflects growth signaling in the body. IGF-1 on a blood test measures the amount of this protein-like factor circulating in the blood, where it is mainly produced in response to growth hormone signals. The IGF-1 test is often used as a stable snapshot of longer-term hormone activity rather than a moment-to-moment change. In a lab report, IGF-1 is usually interpreted with age-based reference data.
Why Is Insulin-Like Growth Factor 1 (IGF-1) Tested?
IGF-1 is commonly ordered as part of a Hormones panel and may also appear in targeted hormone testing. The IGF-1 test helps summarize overall growth-related signaling in the blood and is often reviewed with other hormone markers. On a lab report, Insulin-Like Growth Factor 1 can add context when the pattern of values is being compared across time. It is not part of a CBC, CMP, lipid panel, or thyroid panel, but it may be paired with those panels in broader workups.
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Insulin-Like Growth Factor 1 (IGF-1) Normal Range
| Group | Range | Unit |
|---|---|---|
| Adult Male | 59–204 | ng/mL |
| Adult Female | 59–204 | ng/mL |
Reference ranges may vary by laboratory and individual factors.
What Does High IGF-1 Mean?
High IGF-1 means the measured blood level is above the expected Insulin-Like Growth Factor 1 reference range for the person’s age group. A high IGF-1 test result generally reflects increased growth-signaling activity or a shift in how much of the marker is circulating and bound in blood. For many laboratories, values above the upper limit of the age-based range are considered high IGF-1, though the exact cutoff depends on the method used. On a lab report, high IGF-1 is read as a quantitative change, not as a standalone label.
Associated factors
What Does Low IGF-1 Mean?
Low IGF-1 means the measured value is below the expected Insulin-Like Growth Factor 1 normal range for the person’s age group. A low IGF-1 test result generally reflects reduced growth-signaling activity, lower production, or changes in how much of the marker is circulating in blood. For many laboratories, values below the lower limit of the age-based range are considered low IGF-1. On a lab report, low IGF-1 is interpreted with the reference interval and the rest of the hormone pattern.
Associated factors
How Insulin-Like Growth Factor 1 (IGF-1) Relates to Other Values
IGF-1 is often read with other hormone markers from the same panel, especially growth hormone-related values when available. When IGF-1 is reviewed alongside testosterone, estradiol, and thyroid markers, the combination helps describe broader hormone balance rather than a single number. On a lab report, Insulin-Like Growth Factor 1 on a blood test is also interpreted with age-based norms, because the pattern matters more than one isolated value. If a report includes fasting glucose or HbA1c, those can provide additional context about how the body is handling fuel while IGF-1 reflects longer-term growth signaling.
What Factors Affect Insulin-Like Growth Factor 1 (IGF-1) Levels?
IGF-1 varies with age, sex, body composition, and the lab’s reference method. Time of day usually has less effect than for some other hormones, but recent exercise, food intake, and overall nutrition can still shift the result. Hydration can change the concentration slightly by altering plasma volume, especially when the value is near the edge of the normal Insulin-Like Growth Factor 1 normal range. Pregnancy, smoking, and some medications can also influence IGF-1 on a lab report. Because methods differ, two labs may not give identical IGF-1 test results even from the same sample.
How It Is Tested
The IGF-1 test is performed on a standard blood sample, usually drawn from a vein in the arm. The lab measures the circulating IGF-1 concentration and reports it as a numeric value. Common units include ng/mL, and some laboratories may use nmol/L.
How to Prepare
Fasting is usually not required for an IGF-1 test. The exact collection instructions can vary by laboratory method.
Frequently Asked Questions
What is the normal range for Insulin-Like Growth Factor 1?
What does IGF-1 stand for?
What does a high Insulin-Like Growth Factor 1 mean on a lab report?
What does a low Insulin-Like Growth Factor 1 mean on a lab report?
Can hydration affect Insulin-Like Growth Factor 1?
What is the difference between Insulin-Like Growth Factor 1 and growth hormone?
What unit is Insulin-Like Growth Factor 1 measured in?
How much can Insulin-Like Growth Factor 1 change between tests?
Is Insulin-Like Growth Factor 1 different for men and women?
Why is Insulin-Like Growth Factor 1 tested in a Hormones panel?
What does IGF-1 mean on a blood test?
Disclaimer
This content is for informational and educational purposes only. It is not intended as medical advice, diagnosis, or treatment recommendation. Reference ranges may vary by laboratory. Always discuss your results with a qualified healthcare professional.
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