WHAT IS AN IGF 1 BLOOD TEST?

An IGF 1 blood test measures the level of insulin-like growth factor 1 in your blood. IGF 1 is a hormone that plays an important role in growth, tissue repair, and metabolism. It works closely with growth hormone and is often used as an indirect way to assess how much growth hormone the body is producing over time.

Because growth hormone levels fluctuate throughout the day, measuring IGF 1 provides a more stable picture of growth hormone activity. If you are investigating unexplained symptoms related to growth, metabolism, or hormone balance, a laboratory analysed IGF 1 blood test from One Day Tests offers a reliable way to assess this hormone without needing a GP referral.

IGF 1 is produced mainly by the liver in response to growth hormone released from the pituitary gland. Once released into the bloodstream, IGF 1 helps mediate many of the effects of growth hormone on bones, muscles, and other tissues.

An IGF 1 blood test measures the average level of growth hormone activity rather than moment to moment changes. This makes it particularly useful when investigating conditions linked to too much or too little growth hormone.

The test is used in both children and adults, although the reasons for testing differ depending on age and symptoms.

IGF 1 supports normal growth and development during childhood and adolescence. It helps stimulate bone growth, muscle development, and tissue repair. Levels naturally rise during childhood, peak during puberty, and then gradually decline with age.

In adults, IGF 1 continues to play a role in maintaining bone density, muscle mass, and metabolic health. While lower levels are expected with ageing, abnormally low or high levels can indicate an underlying hormone issue.

Because IGF 1 affects many tissues, changes in its levels can contribute to a wide range of symptoms.

An IGF 1 blood test may be used when symptoms suggest abnormal growth hormone activity.

In children, testing may be considered if growth appears slower than expected or if puberty is delayed. Low IGF 1 levels can help support the investigation of growth hormone deficiency or reduced responsiveness to growth hormone.

In adults, the test may be used when there are features suggestive of growth hormone deficiency, such as reduced muscle mass, low energy, or reduced bone density. It can also be used when there are signs of excessive growth hormone activity.

Low IGF 1 levels can be seen when growth hormone production is reduced or when the body does not respond properly to growth hormone.

In children, this may result in short stature or delayed growth. In adults, low levels may be associated with reduced muscle strength, lower bone density, increased fatigue, and changes in body composition.

Low IGF 1 levels can also be influenced by nutritional status, chronic illness, and certain hormone imbalances, which is why results are always interpreted in context.

High IGF 1 levels usually reflect excessive growth hormone production. In children, this can be associated with unusually rapid or excessive growth.

In adults, elevated IGF 1 levels may be linked to conditions where growth hormone is produced in excess. Symptoms can include changes in facial features, enlargement of hands or feet, joint pain, headaches, and fatigue.

Persistently high IGF 1 levels often require further investigation to identify the underlying cause.

Growth hormone is released in pulses throughout the day and night, meaning a single blood test may not reflect overall production. IGF 1 levels are more stable and reflect average growth hormone activity over time.

This stability makes IGF 1 a more reliable marker when screening for growth hormone related conditions or monitoring long term trends.

In some cases, IGF 1 testing is combined with other hormone tests to provide a more complete picture.

Most people do not need to make special preparations before an IGF 1 blood test. The sample is usually taken from a vein in the arm and the procedure is quick.

If the test is being done alongside other blood tests, you may be advised to follow specific instructions. Any medications or existing health conditions should be taken into account when interpreting results.

IGF 1 reference ranges vary by age and sex, as levels naturally change throughout life. A result that is normal for one age group may be abnormal for another.

Results are interpreted alongside symptoms, medical history, and other test findings. A single result does not usually provide a diagnosis on its own.

In some cases, repeat testing or additional hormone tests may be recommended to confirm findings.

IGF 1 testing is not a routine screening test and is usually requested when there is a specific clinical reason. Mild symptoms without clear indicators of hormone imbalance may be caused by other factors.

Because IGF 1 levels naturally decline with age, lower levels in older adults are often normal and do not necessarily indicate a problem.