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Gamma-Glutamyl Transferase (GGT)

Test ID: A873

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The analysis of gamma-glutamyl transferase (GGT) levels is the most sensitive method for detecting liver disease. It is also a necessary analysis of samples with elevated alkaline phosphatase (ALP) to determine if the ALP abnormalities are due to skeletal disease (normal GGT) or hepatobiliary disease (elevated GGT).



How to order a test


  • γ-Glutamyl Transferase
  • GGT
  • Gamma-GT

What is Included?

Measurement of GGT levels in a blood sample by the L-gamma-glutamyl-3-carboxy-4-nitroanilide substrate methodology.

Turnaround Time

1 – 3 business days
The turnaround time is not guaranteed. The average turnaround time is 1 – 3 business days from the date that the sample arrives at the laboratory. Shipping time for the sample is not included. Additional time is required if the case requires confirmatory or reflex testing, or if the sample is insufficient, or if a recollection is required.

Related Documents

Additional Information and Resources


Preparation Before Specimen Collection

Alcohol consumption can increase GGT levels, and should be avoided prior to collecting the blood sample for this test.

Specimen Type



50 μL in a microtainer


Microtainer (regular blood tube)

Collection Method

This test requires a blood sample from a finger prick. All supplies for sample collection are provided in the kit.

  1. First wash and dry hands. Warm hands aid in blood collection.
  2. Clean the finger prick site with the alcohol swab and allow to air dry.
  3. Use the provided lancet to puncture the skin in one quick, continuous and deliberate stroke.
  4. Wipe away the first drop of blood.
  5. Massage hand and finger to increase blood flow to the puncture site. Angle arm and hand downwards to facilitate blood collection on the fingertip.
  6. Drip blood into the microtainer tube.
  7. Dispose of all sharps safely and return sample to the laboratory in the provided prepaid return shipping envelope.

NOTES: Avoid squeezing or ‘milking’ the finger excessively. If more blood is required and blood flow stops, perform a second skin puncture on another finger. Do not touch the fingertip.

Specimen Storage

Maintain specimen at temperatures between 2°C and 30°C during storage and transport.

Specimen Stability

Blood samples can be refrigerated or kept at room temperature for up to 7 days.

Causes for Rejection

  • Incorrect or incomplete patient identification
  • Incorrect specimen collection
  • Inappropriate storage and transport conditions
  • Incorrect specimen volume
  • Hemolysis



To measure GGT levels in a blood sample predominantly for the detection of liver disease.

GGT levels are elevated in liver disease. Elevated levels (5-30 times normal) are detected in cases of obstructive jaundice and metastatic neoplasms, usually more pronounced, at an earlier stage, and for longer periods than other liver enzymes. Moderate increases (2-5 times normal) are also observed with infectious hepatitis, but transaminase determinations are usually a more effective diagnostic tool for hepatitis. Individuals who consume large quantities of alcohol generally have elevated GGT, particularly those with alcoholic cirrhosis. Specific drugs (e.g. phenytoin and phenobarbital) can also cause an increase in GGT levels.

Elevated GGT is also linked to an increased risk of other diseases and conditions, including atherosclerosis, heart failure, diabetes, metabolic syndrome, and several life-threatening cancers.


  • This report is not intended for use in medico-legal applications.
  • These results should be interpreted in conjunction with other laboratory and clinical information.
  • Correct specimen collection and handling is required for optimal assay performance.
  • Medications that can increase GGT levels include DilantinTM, carbamazepine and phenobarbital, non-steroidal anti-inflammatory drugs (NSAIDs), and cholesterol medications.
  • Elevated GGT levels occur in various health issues, and are not limited to just liver disease. Elevated GGT results must be interpreted in conjunction with other laboratory and clinical data.


L-gamma-glutamyl-3-carboxy-4-nitroanilide substrate methodology (Alinity c Gamma-Glutamyl Transferase assay)

Reference Intervals

Male: 2 – 30 U/L
Female: 1 – 24 U/L

These reference ranges were obtained from Reed R. (2020). Clinical Chemistry Learning Guide Series. Editors Armbruster D & Cooper K. Abbott.