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Gamma Glutamyl Transferase

Alias: GGT, Gamma GT

Discipline: Clinical Chemistry

Test information: GGT is a sensitive indicator of hepatobiliary disease and is often used to determine the origin of elevated serum alkaline phosphatase (ALP) activity. Raised ALP concentrations can be caused by cholestasis, pregnancy (due to the production of placental ALP in the 3rd trimester), or due to rapid bone growth (e.g. adolescence) or bone disease.  A concurrent elevation in GGT alongside ALP confirms the source of ALP as the liver.  In biliary obstruction, serum GGT activity may increase before that of ALP.  GGT is also measured to assess compliance with treatment in alcohol abuse, and the reported sensitivity of a raised GGT for detecting alcohol ingestion has ranged from 52% to 94%.  Although GGT has a high sensitivity for hepatobiliary damage it has poor specificity, which limits its clinical utility.

Specimen Type(s)
  • Blood;
Other Acceptable Specimen Type(s)
Specimen Container - Adult
  • Gold Top SST BD;
Specimen Container - Paediatric
  • Light Green Top Microtainer BD;
  • N/A;
Part of a test profile?
Volume (min) of sample to be sent to laboratory
Patient Preparation, Sample Handling and Transport
Maximum add on time
5 days
Units and Reference Ranges / Interpretation
RR for Male and Female
0 to <15 days - 23  to  219 U/L
15 days to <1yr -  8  to  127 U/L
1yr to <11yr - 6  to 16 U/L
11 yr to <19yrs - 7  to 21 U/L
RR for Female - 19 years and above - Less than 38 U/L
RR for Male - 19 years and above - Less than 55 U/L
UKAS number
UKAS accredited test?

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Last updated: 03-05-2024