Sign in →

Test Mnemonic GGT Gamma-Glutamyltransferase (GGT), Serum

Reporting Name

Gamma Glutamyltransferase (GGT), S

Useful For

Diagnosing and monitoring hepatobiliary disease, it is currently the most sensitive enzymatic indicator of liver disease


Ascertaining whether observed elevations of alkaline phosphatase are due to skeletal disease (normal gamma-glutamyltransferase: GGT) or reflect the presence of hepatobiliary disease (elevated GGT)


A screening test for occult alcoholism

Performing Laboratory

Mayo Medical Laboratories in Rochester

Specimen Type


Necessary Information

Patient's age and sex are required.

Specimen Required


Preferred: Serum gel

Acceptable: Red top

Specimen Volume: 0.5 mL

Collection Instructions:

1. Serum gel tube should be centrifuged within 2 hours of collection.

2. Red-top tube should be centrifuged and aliquoted within 2 hours of collection.

Specimen Minimum Volume

0.25 mL

Specimen Stability Information

Specimen Type Temperature Time
Serum Refrigerated (preferred) 7 days
  Ambient  7 days
  Frozen  7 days

Reference Values


1-6 years: 7-19 U/L

7-9 years: 9-22 U/L

10-13 years: 9-24 U/L

14-15 years: 9-26 U/L

16-17 years: 9-27 U/L

18-35 years: 9-31 U/L

36-40 years: 8-35 U/L

41-45 years: 9-37 U/L

46-50 years: 10-39 U/L

51-54 years: 10-42 U/L

55 years: 11-45 U/L

≥56 years: 12-48 U/L

Reference values have not been established for patients <12 months of age.



>1 year: 6-29 U/L

Reference values have not been established for patients <12 months of age.

Day(s) and Time(s) Performed

Monday through Sunday Continuously

Test Classification

This test has been cleared or approved by the U.S. Food and Drug Administration and is used per manufacturer's instructions. Performance characteristics were verified by Mayo Clinic in a manner consistent with CLIA requirements.

CPT Code Information


LOINC Code Information

Test ID Test Order Name Order LOINC Value
GGT Gamma Glutamyltransferase (GGT), S 2324-2


Result ID Test Result Name Result LOINC Value
GGT Gamma Glutamyltransferase (GGT), S 2324-2

Method Name

Photometric Rate


If not ordering electronically, complete, print, and send a Gastroenterology and Hepatology Test Request Form (T728) with the specimen (