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PTD - 238

Test Directory - Gamma-GT



Clinical Indications

This enzyme is a sensitive marker of liver insult; it is raised in cases of excessive alcohol consumption, when other liver markers may be normal. However gamma-GT is a poor marker of alcohol intake if raised as a result of alcohol damage it may never return to normal, even if total abstinence.

Some drugs (e.g. phenytoin) act as an enzyme inducer and gamma-GT levels may be elevated in the absence of liver pathology.

Gamma-GT is most useful in distinguishing between bone and liver causes of a raised alkaline phosphatase level.

Request Form

Combined Pathology Blood form (Yellow/Black)


On request.

Specific Criteria


Patient preparation


Turnaround Time

Same day




1 ml


Yellow top (SST) tube or

Paediatric orange top (lithium-heparin)

Causes for Rejection

Unlabelled sample.

Reference Range

Males: 10 - 71 IU/L.
Females:  6 - 42  IU/L

Reference: Roche method insert

Lab Handling

Processing: Analysed from primary tube and stored at 4C in the cold room (CB23)

Version 1.1 /  October 2014                                                                                                    Approved by: Consultant Biochemist