From the Guidelines
Testing for acromegaly should begin with measuring insulin-like growth factor-1 (IGF-1) levels in the blood, as elevated levels are a reliable marker for growth hormone (GH) excess, according to a strong recommendation with moderate-quality evidence 1.
Diagnosis of Acromegaly
To diagnose acromegaly, the following steps should be taken:
- Measure serum IGF-1 levels, which should be elevated in relation to the age-adjusted, sex-adjusted, and Tanner stage-matched normal range 1.
- If IGF-1 levels are elevated, perform an oral glucose tolerance test (OGTT) to measure GH levels after consuming glucose, with a cut-off of 1 μg/l for GH suppression 1.
- Interpret biochemical results within a clinical assessment of phenotype, including height velocity, pubertal stage, and bone age 1.
Additional Testing
Once biochemical diagnosis is confirmed, additional tests may include:
- MRI of the pituitary gland to locate the tumor causing excessive GH production 1.
- Visual field testing if the tumor is pressing on the optic nerves.
- Screening for complications like diabetes, heart disease, sleep apnea, and arthritis.
Importance of Early Diagnosis
Early diagnosis is crucial as acromegaly progresses slowly, with symptoms often developing over years before recognition, and can cause characteristic physical changes and systemic complications if left untreated 1.
Monitoring and Treatment
Both GH and IGF-1 levels should be monitored at baseline and during follow-up in patients with GH excess, as baseline GH levels are predictive of surgical outcome and are key to monitoring the hormone-producing activity of the adenoma 1. The goal of medical treatment is to reduce fasting morning GH and IGF-I concentrations to levels that are as close to normal as possible, following the recommendations of previous consensus meetings 1.
From the FDA Drug Label
The FDA drug label does not answer the question.
From the Research
Testing for Acromegaly
To test for acromegaly, several methods can be employed, including:
- Measuring serum Insulin-like Growth Factor-1 (IGF-1) levels, which is a reliable marker of disease activity and growth hormone (GH) status in acromegaly 2
- Conducting an oral glucose tolerance test (OGTT) to assess GH suppression, as elevated IGF-1 levels alone are sufficient to establish a diagnosis of acromegaly in the majority of clinically suspected cases 3
- Using a combination of these tests to confirm the diagnosis, as the OGTT may be useful to obtain corroborative evidence when there is modest elevation of IGF-1 with absent or equivocal clinical features 3
Biochemical Assessments
Biochemical assessments, such as measuring GH and IGF-1 levels, are crucial for therapeutic monitoring in acromegaly 4. These assessments help to:
- Evaluate the effectiveness of treatment
- Monitor disease activity
- Detect potential recurrence of the disease
Importance of Monitoring
Regular monitoring of GH and IGF-1 levels is essential for patients with acromegaly, even those without clinical symptoms of disease, to maintain biochemical control and prevent the risk of developing recurrent disease 4. Suboptimal monitoring can have negative health effects due to delays in detection of recurrent disease and implementation of appropriate treatment.
Diagnostic Tests
Several diagnostic tests are available to support the diagnosis of acromegaly, including: