Gamma-Glutamyl Transferase (GGT)
CPT Code(s):
82977
Turnaround Time:
4 hours
Specimen Requirements
Preferred Specimen:
Serum
Minimum Volume:
1.0 mL
Transport Container:
Serum Separator Tube (SST) or Red Top Tube
Transport Temperature:
Room Temperature
Collection Instructions:
Allow blood to clot completely prior to centrifugation. Separate serum from cells within 45 minutes of collection.
Rejection Criteria:
Citrate, Fluoride,Sodium Heparin, or EDTA plasma specimen; gross hemolysis; lipemia; improper labeling
Stability Criteria
Room Temperature:
7 days
Refrigerated:
7 days
Frozen:
30 days
Clinical Significance
The Gamma-Glutamyl Transferase (GGT) test holds specific clinical significance and diagnostic use in assessing liver function and diagnosing liver disorders. GGT is an enzyme found predominantly in the liver, and its levels in the blood can provide important insights into liver health and certain medical conditions.
The specific clinical significance and diagnostic use of GGT include:
1. Liver Function Assessment: GGT is commonly used as a marker of liver function. Elevated GGT levels can indicate liver damage or dysfunction. When used in conjunction with other liver function tests, such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), GGT helps healthcare providers evaluate the overall liver function and assess the severity of liver disease.
2. Liver Disease Diagnosis: GGT levels are particularly elevated in certain liver conditions, such as alcoholic liver disease, hepatitis, and bile duct disorders. GGT aids in diagnosing these liver diseases and differentiating between various causes of liver dysfunction.
3. Alcohol Abuse Screening: GGT levels are sensitive to alcohol consumption. GGT is often used as a marker for alcohol abuse or heavy alcohol consumption. Elevated GGT levels in individuals with no other apparent liver disease can indicate alcohol-related liver damage.
4. Monitoring Liver Health: GGT is useful in monitoring liver health and disease progression. Serial measurements of GGT levels over time can help track changes in liver function, assess response to treatment, and monitor the impact of lifestyle modifications or medications on liver health.
5. Differential Diagnosis: Elevated GGT levels can occur in conditions other than liver disease. GGT assists in ruling out non-liver causes of GGT elevation, such as certain medications, pancreatitis, and cardiovascular diseases. It aids in the differential diagnosis by providing additional information to healthcare providers.
6. Prognostic Indicator: GGT levels can serve as a prognostic indicator in certain liver diseases. Higher GGT levels are associated with increased liver disease severity, worse prognosis, and higher risk of complications in conditions such as non-alcoholic fatty liver disease (NAFLD) and alcoholic liver disease.
It is important to note that elevated GGT levels need to be interpreted in the context of the patient's clinical presentation, medical history, and other liver function test results. Further diagnostic tests may be required to determine the underlying cause of GGT elevation and guide appropriate management.
In summary, GGT has specific clinical significance in assessing liver function, diagnosing liver disorders, screening for alcohol abuse, monitoring liver health, aiding in differential diagnosis, and serving as a prognostic indicator. By measuring GGT levels in a patient's blood, this test provides valuable information for clinical decision-making, liver disease diagnosis, and optimizing patient care outcomes related to liver health.