GGT (Gamma-glutamyl transpeptidase) (GGTP)
GGT (aka Gamma-glutamyl transpeptidase, GGTP) helps to detect liver and bile duct injury as well as chronic alcohol abuse (it will be elevated in about 75% of chronic drinkers). GGT may be used to monitor compliance with an alcohol treatment program. Both ALP and GGT are elevated in disease of the bile ducts and in some liver diseases, but only ALP will be elevated in bone disease. If GGT is normal in a person with a high ALP, the cause is most likely bone disease.
A doctor usually orders GGT along with other tests to evaluate a person who has signs or symptoms suggestive of liver disease. Some of the symptoms of liver injury include jaundice, nausea, vomiting, abdominal swelling, abdominal pain, severe itching, and fatigue.
GGT is increased in most diseases that cause acute damage to the liver or bile ducts, but is usually not helpful in distinguishing between different causes of liver damage. For this reason, use of GGT is controversial, and the use of GGT is not universal. It can be useful in determining the cause of a high ALP. In persons with a history of alcohol abuse who have completed alcohol treatment.
Because reference values are dependent on many factors, including patient age, gender, sample population, and test method, numeric test results have different meanings in different labs. Your lab report should include the specific reference range for your test. standard reference range is not available for this test.
Doctors are not usually concerned with low or normal levels, but they do indicate that it is unlikely that a patient has liver disease. Elevated GGT levels indicate that something is going on with the liver but the test is not specific to a particular disease. In general, the higher the level the greater the “insult” to the liver. Elevated levels may be due to liver disease, but they may also be due to congestive heart failure, alcohol consumption, and use of many prescription and non-prescription drugs including nonsteroidal anti-inflammatory drugs (NSAIDs), lipid-lowering drugs, antibiotics, histamine blockers (used to treat excess stomach acid production), antifungal agents, seizure control medications, antidepressants, and hormones such as testosterone. Oral contraceptives and clofibrate can decrease GGT levels.
Even small amounts of alcohol within 24 hours of your GGT test may cause a temporary increase in the GGT. If this occurs, your doctor may want to repeat the test to verify that it is normal. Smoking can also increase GGT. GGT is about twice as high in persons of African ancestry as in those of European ancestry. Levels of GGT increase with age in women, but not in men, and are always somewhat higher in men than in women.