From the Guidelines
Elevation of Gamma-Glutamyl Transferase (GGT) and Alkaline Phosphatase (Alk Phos) typically indicates liver or biliary tract problems, particularly cholestatic liver disease, as supported by the most recent study 1. When both GGT and ALP are elevated, it suggests that the liver is the source of the elevated ALP, indicating cholestasis. The causes of this elevation can be varied, including:
- Cholestatic liver disease, such as primary biliary cholangitis, primary sclerosing cholangitis, intrahepatic or extrahepatic bile duct obstruction, and drug-induced cholestasis
- Extrahepatic biliary obstruction, with choledocholithiasis being the most common cause
- Infiltrative liver diseases, such as sarcoidosis, amyloidosis, and hepatic metastases
- Other liver diseases, including hepatitis, cirrhosis, and liver cancer
According to the study 1, measurements of GGT can help confirm whether an elevated ALP is of hepatic or nonhepatic origin, as GGT is not found in bone. Concomitantly elevated GGT can help confirm that an elevated ALP originates from the liver and indicates cholestasis. If the liver is suspected to be the source of elevated ALP, imaging of the biliary tree may be necessary to determine the etiology of extrahepatic or intrahepatic cholestasis 1.
It is essential to consult a healthcare provider promptly for proper evaluation if elevated levels of GGT and ALP are detected. They will likely order additional tests, such as bilirubin levels, other liver enzymes, ultrasound, or CT scans, to determine the exact cause. While waiting for the appointment, avoiding alcohol, reviewing medications with the doctor, and maintaining a healthy diet are recommended. The pattern and degree of elevation can help pinpoint the specific issue, with a greater increase in ALP than GGT suggesting bone disease rather than liver problems, and significant elevation of both typically pointing to biliary obstruction 1.
From the Research
Elevation of Gamma-Glutamyl Transferase (GGT) and Alkaline Phosphatase (Alk Phos)
- An elevation of GGT and Alk Phos can indicate liver damage or disease, particularly cholestasis, which is a condition where bile flow is reduced or blocked 2.
- In patients with metastatic pancreatic cancer, high levels of ALP and GGT are associated with a poor prognosis, especially in those with liver metastasis 3.
- Elevated serum levels of GGT and ALP can also be seen in acute cholecystitis and common bile duct stone, with a more than 2.5-fold increase in ALP levels predicting the presence of a common bile duct stone 4.
- The combination of serum GGT and ALP has been shown to be useful in predicting the diagnosis of asymptomatic choledocholithiasis secondary to cholecystolithiasis, with a sensitivity of 93.5% and specificity of 85.1% 5.
- A marked increase in GGT, even if conventional diagnostic criteria for acute liver injury are not met, can be an indicator of drug-induced liver injury (DILI) and may require discontinuation of the causative drug or close monitoring of the patient 6.
Possible Causes
- Cholestasis
- Liver damage or disease
- Acute cholecystitis
- Common bile duct stone
- Metastatic pancreatic cancer
- Drug-induced liver injury (DILI)
Diagnostic Value
- Elevated GGT and ALP levels can be used as indicators of liver damage or disease
- The combination of serum GGT and ALP has better diagnostic performance than either marker alone in predicting asymptomatic choledocholithiasis secondary to cholecystolithiasis 5
- A marked increase in GGT can be an indicator of DILI, even if conventional diagnostic criteria are not met 6