Gamma Glutamyl Transferase (GGT)

γ-Glutamyl Transferase (GGT) CPT: 82977


Gamma-Glutamyl Transferase

Glutamyl Transpeptidase

Expected Turnaround Time

Within 1 day

Specimen Requirements




1 mL

Minimum Volume

0.5 mL


Red-top tube, gel-barrier tube, green-top (heparin) tube, or lavender-top (EDTA) tube


Separate serum or plasma from cells within 45 minutes of collection.

Storage Instructions

Room temperature

Stability Requirements

Patient Information

To evaluate for a possible liver disease or bile duct disease or to differentiate between liver and bone disease as a cause of elevated alkaline phosphatase (ALP); sometimes to screen for or monitor alcohol abuse.

When you have symptoms of a liver or bile duct disorder or as follow up when you have an increased ALP level.

A blood sample drawn from a vein in your arm.

GGT levels fall after meals; you may be instructed to fast (nothing to eat or drink except water) for at least 8 hours prior to the test. You may also be asked to stop drinking alcohol or taking certain prescription medications.