Gamma GT (GGT, ƴGT)
Chemical Pathology
Notes
- Gamma GT ( ƴGT) is increased in most diseases that cause acute damage to the liver or bile ducts, but is not usually helpful in distinguishing between different causes of liver damage.
- This test is not part of the routine liver profile but must be requested separately.
- ƴGT is often used in identifying/monitoring alcohol use but has limited sensitivity and specificity. In difficult cases an early morning alcohol level may help.
- ƴGT is useful in distinguishing between liver and bone disease as a cause of elevated alkaline phosphatase levels.
- ƴGT can be elevated in chronic heart failure and also by many drugs.
Sample requirements
For adults, blood taken into a 5mL gold top tube (or rust top for the Acute Unit)
For children, blood taken into a 3.5mL rust top tube
For neonates, blood taken into a 0.8mL minicollect lithium heparin tube. Please list the tests of particular interest so that some priority can be given to analysis if plasma volumes are small.
Storage/transport
Send at ambient temperature to the laboratory. If unavoidable samples can be stored refrigerated overnight.
Required information
Relevant clinical details including relevant medication.
Turnaround times
The assays are run throughout the day and night.
The in-lab turnaround time is normally less than 24 hours.
The test can be ordered as an urgent request.
Reference ranges
| Age/Gender | Reference range | Units |
|---|---|---|
| < 1 month | 12 - 271 | U/L |
| 1m - 2m | 9 - 159 | U/L |
| 2m - 4m | 2 - 98 | U/L |
| Male 4m - 18y | < 45 | U/L |
| Male > 18y | < 61 | U/L |
| Female 4m - 18y | <30 | U/L |
| Female >18y | < 36 | U/L |