Description
Why It’s Done
The GGT test may be ordered to:
• Detect Liver or Bile Duct Disorders: Especially when other liver enzyme levels (like ALP) are elevated.
• Evaluate Alcohol Abuse: Chronic alcohol use can increase GGT levels.
• Monitor Liver Function: Especially in people taking medications that can affect the liver.
• Help Diagnose Causes of Jaundice: Or unexplained liver test abnormalities.
• Assess Bile Duct Blockages: Such as from gallstones or tumors.
It is particularly useful in differentiating the source of an elevated alkaline phosphatase (ALP) — whether it’s liver or bone-related.
Preparation
To prepare for the GGT test:
• Fasting: You may be asked to avoid eating or drinking (except water) for 8 hours before the test.
• Avoid Alcohol: Refrain from consuming alcohol for at least 24 hours before the test, as it can raise GGT levels.
• Medication Disclosure: Inform your doctor about any medications or supplements you’re taking, as some (like phenytoin, barbiturates, or NSAIDs) can affect GGT levels.
• Avoid Smoking Before the Test: As it may also slightly increase GGT levels.


