Gamma GT

Gamma-Glutamyl Transferase (GGT) is a microsomal enzyme involved in glutathione metabolism.
It is mainly present in:

• Liver (especially bile duct epithelial cells)
• Kidney
• Pancreas
• Intestine

Clinically, it is most useful as a marker of hepatobiliary disease.

1️⃣ Marker of Cholestasis (Very Important)

GGT rises markedly in:

• Obstructive jaundice
• Intrahepatic cholestasis
• Bile duct obstruction
• Drug-induced cholestasis

🔎 It is highly sensitive for biliary tract disease.

2️⃣ Differentiation of Liver vs Bone ALP Elevation

Both ALP and GGT increase in liver disease.

Condition :
Liver disease 
Bone disease 

👉 If ALP is elevated and GGT is also elevated → Hepatic origin
👉 If ALP is elevated but GGT normal → Bone disease

This makes GGT very useful in clinical interpretation.

3️⃣ Alcoholic Liver Disease

GGT is markedly elevated in:

• Chronic alcohol consumption
• Alcoholic hepatitis
• Alcoholic cirrhosis

📌 Often used as a marker of alcohol abuse.
Levels may normalize after abstinence.

4️⃣ Drug Induction

Increased in patients taking:

• Phenytoin
• Barbiturates
• Carbamazepine

Because GGT is a microsomal enzyme induced by drugs.

5️⃣ Hepatocellular Disease

Moderate elevation seen in:

• Viral hepatitis
• Fatty liver
• Cirrhosis

Normal Reference Range :

• Males: ~10–71 IU/L
• Females: ~6–42 IU/L
  (Range varies by laboratory)