Gamma Glutamyl Transferase (GGT) Lab Values

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Determine the significance and clinical use of the lab value of Gamma Glutamyl Transferase in clinical practice.


Lab Test Name:

Gamma Glutamyl Transferase – GGT



Measurement of GGT enzyme in the blood

  • Enzyme most abundantly found in the liver
  • Disease process of: liver, biliary tract and pancreas
  • 75% of people with alcohol abuse disorder have elevated levels of GGT in their blood
  • A.K.A gamma-glutamyl transpeptidase



Indications to test GGT:

Liver disease 

  • Abnormal LFTs
  • N/V
  • Abdominal pain
  • Itchy skin
  • Jaundice
  • Fatigue
  • Loss of appetite
  • ETOH abuse
  • Drug overdose
  • Bone disease- when combined with ALK Phos, GGT will not be elevated in bone disease
  • Damage to the liver’s bile ducts


Normal Therapeutic Values:


Normal: 5- 40 U/L


  • Serum separator


What would cause increased levels?

Elevated GGT

Disease process:

  • Liver disease/cancer- cirrhosis, hepatitis, fibrosis
  • Cholestasis
  • Pancreatitis

Non-disease process

  • Smoking- significantly associated with increased levels of GGT
  • Alcohol abuse disorder
  • Medications- acetaminophen, barbiturates – medications that are metabolized through the liver


What would cause decreased levels?

Decreased GGT

  • Unbalanced diet
  • Vitamin or mineral deficient
  • Not linked to medical condition or disease

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Hey everyone. Abby here with Our lab lesson is going to cover a lab for Gamma Glutamyl Transferase abbreviated, GGT. Let’s get started. The GGT lab measures the amount of gamma glutamyl transferase in the blood. It’s an enzyme found most abundantly in the liver  in addition to other tissues. It indicates if there’s a disease process of the liver, the bile ducts, or pancreas. It’s often seen or monitored in those with alcohol abuse disorder. It can also be implemented as a way to differentiate between if it’s liver or bone disease, as it can be measured alongside an Alk Phos lab.


Now, if we’re talking liver, what type of clinical presentation do you think we’re going to see in our patient? If you said jaundice, you’re right. With liver disease, we’re going to see patients with jaundice, they could have itchy skin, abdominal pain. They might even have Ascites. Remember when the abdomen is full of fluid, not that it would look like that. <laugh> um, we’d also see, of course, as I mentioned, if someone came in and was seeking treatment for alcohol abuse disorder, uh, the GGT is monitored. And if a patient has a drug overdose, we know that medications are metabolized by the liver. And the GGT can tell us how those hepatocytes are actually responding. We talked about bone disease differentiation because GGT won’t be present if someone has bone disease with an elevated Alk Phos. It also would be indicated in someone of biliary tract damage.They’re going to have a lot of abdominal pain. Pretty typical.


Normal therapeutic values are between 5 and 40 units per liter. It’s collected in a serum separator tube. Lab values will be increased when there’s a disease process of the liver. Most often, it could also be in cases of pancreatitis. Liver diseases are going to be cirrhosis, hepatitis fatty, liver disease, even if it’s non-alcoholic and if there’s tumors or cancer present, Cholestasis is when the bile ducts are blocked. And, that is also going to increase our GGT value. Now, it’s not always a disease process that causes an increase in these lab values. It could be someone that’s smoking, certain medications, and then it’s definitely present in someone that has recently consumed a large amount of alcohol. This lab value would be decreased if someone has malnutrition. So, that means that the liver isn’t metabolizing as well. It can also be completely unrelated to disease. GGT, remember the gamma glutamyl transferase, it’s an enzyme that’s measured in the blood that’s most abundantly present in liver tissue produced by hepatocytes. Our normal value is between 5 and 40 units per liter, and it’s related in its increased value to alcohol consumption and liver disease presentation. Malnutrition is often the cause of a decreased value. Now, you all did so great today. We love you guys now, go out and be your best self and as always, happy nursing!



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