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This website is intended for an international audience, excluding the United States, Canada and France

Growth hormone and IGF-1

Growth hormone and insulin-like growth factor 1 (IGF-1) are measured in micrograms per litre of blood (μg/L). IGF-1 may also be measured as nanomoles per litre (nmol/L), which is a different way of expressing its concentration.

What are normal levels of growth hormone?

It is hard to define, what a “normal” level of growth hormone is, because the hormone is secreted in bursts and does not stay in the blood stream for long. This is why a random growth hormone level cannot be used as the only laboratory value to find out whether a person has acromegaly or not.

An oral glucose tolerance test (OGTT) will give better information of whether a person has an overproduction of growth hormone that is characteristic of active acromegaly.

This is because the normal secretion of growth hormone by the pituitary is suppressed by the presence of large amounts of glucose in the bloodstream.

There are different cut-offs to which growth hormone should be suppressed during the test. The critical cut off is a growth hormone level higher than 1 μg/L. Ask your health care professional to explain the test result to you.

What are normal levels of IGF-1?

IGF-1 levels depend on a person’s age and sex, but also on the test kit (called an assay) the laboratory uses.

Adolescents have the highest levels of IGF-1, peaking around the age of 13 to 15 years. IGF-1 levels then decline and become lower with increasing age.

Usually, the laboratory will provide the normal range for its test, according to the sex and age of a person, together with the actual IGF-1 test result.

 

 

What is biochemical control?

One of the goals of acromegaly treatment is to achieve biochemical control or biochemical normalisation.

This is where levels of both growth hormone and IGF-1 are reduced to be within the normal range.

The aim is to get levels of growth hormone to be less than 1.0 μg/L but may vary depending on international guidelines and local practices.

IGF-1 should be reduced to a level that would be normal for the age and sex of the person.

 

Blood sugar (glucose)

The amount of glucose in your blood may be routinely monitored if you have, or are at risk for developing, diabetes mellitus. This is a common coexisting condition that people with acromegaly may have.

There are three ways of measuring your blood glucose:

Blood pressure

Blood pressure results are given as millimeters of mercury, or mmHg. There are two numbers usually written one on top of the other or with one given before the other.

The top or first (<120 in the example given) number gives a measure of the highest pressure when blood is pumped from the heart out into the bloodstream. This is called the systolic blood pressure.

The bottom or second number (<80 mmHg in the example given) gives a measure of the pressure in the arteries when the heart is resting between beats. This is called the diastolic blood pressure.

For most young people without any form of illness the systolic blood pressure should be less than 120 mmHg and the diastolic blood pressure should be less than 80 mmHg.

Hypertension, which is a common comorbidity associated with acromegaly, occurs when these blood pressure values rise to be 140 mmHg or higher and 90 mmHg or higher, respectively.

Body mass index

Your doctor may use your height and weight to calculate your body mass index, or BMI.

This is an approximate measure of whether someone is underweight, of normal weight, or overweight.

 

However, because of the type of body changes that can occur in people with acromegaly the BMI may be a less reliable indicator of their body weight.

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Ipsen
Please always consult a healthcare professional if you require healthcare advice or if you have any specific concerns regarding your acromegaly, its treatment or side effects. The information provided here is not intended to replace professional advice. This website has been developed by Ipsen in collaboration with those living with acromegaly and the healthcare professionals who care for them. Ipsen would like to thank everyone for their valuable insights and stories. All names used on this website are not necessarily real names. Visit our website for more information about us, or to contact us directly. Website design and development by Kanga Health Ltd. Website reference SOM-ALL-000556