Gamma-Glutamyl Transferase (GGT)
GGT is strongly right-skewed and rises with age, particularly in males, reflecting alcohol exposure, metabolic liver disease, medication effects, and cholestatic processes across the population.
Unit: U/L · 12 slices · age and sex · 1 source
Filed under panels: Liver Function , Metabolic Panel · topics: Liver , Metabolic
Gamma-glutamyl transferase (GGT) is a liver and biliary enzyme measured on the standard chemistry panel. It is highly sensitive to alcohol exposure, metabolic dysfunction, medication effects, and cholestatic disease, which gives the population distribution a pronounced right tail. These percentiles describe the full US population rather than a screened healthy subgroup.
Population Distribution
Browse by Demographic
| Age (years) | male (U/L) | female (U/L) |
|---|---|---|
| 20-29 | 11–80 (21) | 7–49.4 (14) |
| 30-39 | 12–103 (26) | 8–43 (15) |
| 40-49 | 12–105.5 (26) | 7–57 (15) |
| 50-59 | 13–116 (27) | 9–74 (20) |
| 60-69 | 11.6–91.7 (24) | 9–59 (18) |
| 70+ | 11–81 (22) | 9–57.9 (17) |
Frequently Asked Questions
Why is GGT so right-skewed?
Most adults have modest GGT values, but alcohol use, steatotic liver disease, medication exposure, cholestasis, and chronic cardiometabolic disease push a smaller subgroup much higher. That creates a long upper tail.
Why is GGT usually higher in males?
At the population level, males have more of the exposures that shift GGT upward, especially alcohol-related and metabolic-liver contributors, so the whole distribution tends to sit higher.
How is GGT used with ALP?
A high ALP with a high GGT points more strongly toward a hepatobiliary source. A high ALP with a normal GGT makes a bone source more plausible.