4727.0.55.002 - Australian Aboriginal and Torres Strait Islander Health Survey: Users' Guide, 2012-13

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Contents >> Biomedical Measures >> Liver function biomarkers >> Gamma-glutamyl transferase (GGT)

GAMMA-GLUTAMYL TRANSFERASE (GGT)

Definition

The liver works as the body's filter, removing toxins from the blood, processing nutrients and regulating its metabolism. When the liver is inflamed or damaged, enzymes including gamma-glutamyl transferase (GGT) leak from the liver cells into the bloodstream. As a result, elevated levels of GGT in the bloodstream can indicate the presence of liver disease, which may have been caused by heavy alcoholism, fatty liver disease (alcohol or non-alcohol related), hepatitis, or a combination of other causes.^1,2 GGT is used widely to determine liver damage³ and is a sensitive indicator of heavy alcohol intake.⁴

The GGT test measures the amount of GGT circulating in the blood at the time of the test.

Population

GGT results were obtained for selected persons aged 18 years and over, who agreed to participate in the National Aboriginal and Torres Strait Islander Health Measures Survey (NATSIHMS) and who provided a blood sample. Fasting was not required for this test.

Methodology

A blood sample was collected from participants and GGT levels were measured at the Douglass Hanly Moir (DHM) laboratory.

There is no consensus on the cut off reference values for defining abnormal GGT levels, as there are currently a number of different methods that can be used to measure GGT. As such, cut off reference values for normal and abnormal results were sourced from DHM laboratory reference ranges.

In the NATSIHMS, the following definitions were used for serum GGT:

Cut off points for GGT in the NATSIHMS


	GGT levels for females (U/L)	GGT levels for males (U/L)

Normal	≤35	≤50
Abnormal	>35	>50

Further test information about the analysis method and machine used to measure GGT levels is available in Excel spreadsheet format in the Downloads page of this product.

Data items

The data items and related output categories for this topic are available in Excel spreadsheet format from the Downloads page of this product.

Interpretation

Points to be considered when interpreting data for this topic include the following:

GGT results do not confirm a specific diagnosis without consultation with a health professional.
There are a number of different test methods for measuring GGT, which may produce different results. The data from this topic should therefore be used with caution when comparing GGT results from other studies using a different test method or equation.

Comparability with other surveys

The NATSIHMS is the first ABS Aboriginal and Torres Strait Islander survey to collect biomedical information. Given it was also the first national level survey (ABS or otherwise) to collect such data for the Aboriginal and Torres Strait Islander population, no comparisons with previous surveys for this population are possible.

However, biomedical data was also collected for all Australians in the 2011-12 National Health Measures Survey (NHMS) and information about comparisons between the NHMS results and those of non-ABS surveys is available from the Comparisons with other Australian surveys section of the Biomedical Results for Chronic Diseases, 2011-12 publication.

ENDNOTES

1 Everhart J and E Wright 2012. Association of γ-glutamyltransferase (GGT) activity with treatment and clinical outcomes in chronic hepatitis C (HCV). Hepatology: Official Journal of the american Association for the Association for the study of Liver Diseases <http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3624035/>, Last accessed 08/09/2014.
2 Torkadi P, Apte IC and AK Bhute 2013, Biochemical Evaluation of Patients of Alcoholic Liver Disease and Non-alcoholic Liver Disease. Indian Journal of Clinical Biochemistry, <http://www.ncbi.nlm.nih.gov/pubmed/24478554>, Last accessed 08/09/2014.
3 Higgins C, 2013, Understanding Laboratory Investigations, A Guide for Nurses, Midwives and Healthcare professionals, 3rd Edn. Wiley-Blackwell, p188.
4 Whitfield JB 2001, Gamma glutamyl transferase. Critical Reviews in Clinical Laboratory Sciences. 38:4 pp 263-355.<http://152.98.160.29/contents/p/staff/JW087.pdf>, Last accessed 08/09/2014.