Exams and Tests

Acromegaly is not an easy diagnosis, and it is often missed by health care providers. Some of the signs and symptoms of acromegaly are very distinctive. Others are subtle and can be misinterpreted. They are not always recognized as acromegaly because they develop so slowly. Enlargement of the hands, feet, or face is most often caused by accumulation of fluid in edematous states, but it can also be a finding of growth hormone excess from acromegaly. 

If suspicious, your health care provider may ask you about your symptoms, your other medical problems now and in the past, your family members’ medical problems, what medications you take, your work history, your habits and lifestyle, and many other questions. A detailed physical examination will look for signs and symptoms that clarify the diagnosis.

Lab tests

If your health care provider suspects acromegaly, he or she will order blood tests to help confirm that diagnosis.

Random measurement of growth hormone in the blood is usually not useful, as levels of the hormone fluctuate unpredictably. IGF-1 level is much more stable and predictable than growth hormone level. Thus, measurement of IGF-1 level is considered the most reliable test for acromegaly.

• IGF-1 and growth hormone levels together usually are used to confirm the diagnosis of acromegaly.
• 
  
• Your health care provider may decide to measure your levels of IGF-binding protein-3 (IGFBP-3), a protein that interacts with IGF-1. Sometimes this can help confirm the diagnosis of acromegaly.

Because growth hormone secretion is inhibited by glucose (blood sugar), some health care providers measure what is called "glucose nonsuppressibility."

• First, your baseline growth hormone level is checked randomly at least twice.
  
  
• It is then checked again just before and several times in the hours after you drink a special high-sugar drink that causes the blood sugar level to rise.
  
  
• The high blood sugar level suppresses the growth hormone level in healthy people but not in people who have too much growth hormone.

The following tests may be ordered if your health care provider thinks they would be helpful:

• GHRH level
• 
  
• Other hormones: These tests may be helpful in ruling out other disorders that are similar to acromegaly.
• 
  
• Cholesterol and triglyceride levels

Imaging studies

After acromegaly has been confirmed by growth hormone and IGF-1 levels, you will probably undergo a CT scan or MRI of the head to confirm that you have an adenoma in your pituitary gland. If no pituitary tumor is detected, your health care provider will continue searching until the source of the excess growth hormone is found.

• CT scans of the abdomen and pelvis look for tumors of the pancreas, adrenal glands, or ovaries that might secrete growth hormone or GHRH.
• 
  
• CT scan of the chest looks for lung cancer, which also can secrete growth hormone or GHRH.