Growth Hormone Suppression Test (GHST) Overview: The Growth Hormone Suppression Test is primarily used to evaluate the function of the pituitary gland and diagnose conditions such as acromegaly or gigantism. It assesses whether growth hormone (GH) levels appropriately decrease in response to an oral glucose load. Normally, glucose administration suppresses GH secretion; failure to suppress GH may indicate a disorder such as acromegaly.

Test Procedure:

1. A baseline blood sample is drawn to measure GH levels.
2. The patient is given a glucose solution (usually 75g or 100g).
3. Subsequent blood samples are collected at specific intervals (e.g., 30, 60, 90, 120 minutes) to measure GH levels.

Risk Assessment:

• Low Risk: Generally, the test is safe with minimal risks.
• Potential Risks: Nausea, vomiting, or dizziness due to the glucose load.
• Contraindications: Severe diabetes, uncontrolled blood sugar levels, or severe insulin resistance may affect the test results.

Normal Range:

• GH levels should suppress significantly after glucose intake, typically to <1 ng/mL (nanograms per milliliter).
• Values above 1 ng/mL after glucose intake may suggest abnormal GH secretion, such as in acromegaly.

Interpretation:

• Normal Result: Significant suppression of GH (<1 ng/mL) following glucose administration.
• Abnormal Result: Failure to suppress GH to below 1 ng/mL, suggesting potential pituitary dysfunction or acromegaly.

Sample Type:

• Blood sample, typically collected in an EDTA or serum tube, at various time intervals after the glucose load.