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This website is intended for an Australian and New Zealand audience who are interested in acromegaly

Growth hormone and IGF-1

Growth hormone and insulin-like growth factor 1 (IGF-1) may be measured in micrograms per litre of blood (mg/L) or nanomoles per litre (nmol/L).

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 single 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’s body is producing too much growth hormone that is characteristic of active acromegaly.  In someone without acromegaly, a higher blood glucose level usually causes the body to stop producing growth hormone. If the growth hormone level is higher than 1 mg/L, this suggests you have acromegaly. Ask your doctor 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.

 

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:

Fasting glucose test

This is where the level of glucose in your blood is measured after you have not eaten or drunk anything other than water for several hours or overnight.

Results are usually given as millimoles per litre (mmol/L).

  • A fasting value of between 3.0 and 5.4 mmol/L is considered normal
  • Fasting values between 6.1 and 6.9 mmol/L indicate impaired fasting glucose in the body
  • Fasting values of 7.0 mm/L or above on two separate tests are indicative of diabetes mellitus

Oral Glucose Tolerance Test (OGTT)

This is the same test that is used for measuring growth hormone suppression. It will also give information on whether your body is capable of clearing glucose away from blood quickly. Your blood glucose levels are again checked after not eating for a few hours, then rechecked 2 hours after you have had the glucose drink.

  • A blood glucose level of less than 7.8 mmol/L at 2 hours is considered normal
  • A value at 2 hours between 7.8 and 11.0 mmol/L shows there is impaired glucose tolerance
  • A value at 2 hours of 11.1 mmol/L or higher, suggests that the individual has diabetes mellitus

HbA1c test

HbA1c, which is also known as glycated haemoglobin, is something that’s made when the glucose in your body sticks to your red blood cells.  If your body can’t use the glucose properly, more of it sticks to your blood cells and builds up in your blood.

Red blood cells are active for around 2-3 months.  HbA1c is your average blood glucose levels over the life of the red cells.

HbA1c is usually measured in people who already have diabetes mellitus to give an accurate picture of their blood glucose control.

Results may be written as a percentage or as a number in millimoles per mole (mmol/mol). A value of 8% or less indicate good control of the diabetes.

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.

Blood pressure over 140/90mmHg is generally considered to be high.

High blood pressure (also known as hypertension) is a common comorbidity associated with acromegaly.

Body mass index

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

BMI 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 supported by Thrivase Pty Ltd.

SOM-AU-000711. Last reviewed: November 2023

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