LIVER FUNCTION BIOMARKERS
The liver works as the body's filter, removing toxins from the blood, processing nutrients and regulating its metabolism. A range of factors, including fatty liver disease, infections and excessive alcohol consumption can prevent the liver from performing these functions and if left untreated, can lead to liver damage.1 When the liver is inflamed or damaged, enzymes including alanine aminotransferase (ALT) and gamma glutamyl transferase (GGT) leak from the liver cells into the bloodstream. As a result, elevated levels of ALT and GGT in the bloodstream can indicate the presence of liver disease.
The National Health Measures Survey (NHMS) provides an objective measurement of the number of people in Australia with ALT and GGT levels that indicate reduced liver function and the presence of liver damage. While elevated levels for either test may indicate liver damage, they cannot diagnose the presence of liver disease.
Alanine aminotransferase (ALT) and Gamma glutamyl transferase (GGT)
Liver disease has many health concerns and elevated ALT and GGT levels are not only associated with liver damage, but also with type 2 diabetes mellitus, cardiovascular disease, stroke and metabolic syndrome.2,3 An elevated ALT or GGT level indicates damage to the liver, which may have been caused by heavy alcoholism, fatty liver disease (alcohol or non-alcohol related), hepatitis, or a combination of other causes.4,5
Comparability with other surveys
The NHMS is the first ABS survey to collect biomedical data on liver function.
Liver function biomedical data has been collected in other non-ABS surveys. However, caution must be taken when interpreting results due to the differences in scope, assay and the instrument used, and any thresholds applied in the final analysis.
More information regarding the biomedical tests and cut off points can be found in the relevant subsections.
1 Angulo P and KD Lindor 2002, Non-alcoholic fatty liver disease, Journal of Gastroenterology and Hepatology, <http://www.gastrohep.com/conreports/bangkok/jghs2.pdf>, Last accessed 01/08/2013
2 Goessling W, Massaro JM, Vasan R.S, D’Agostino RB, Ellison RC and CS Fox 2008. Aminotransferase Levels and 20-year Risk of Metabolic Syndrome, Diabetes, and Cardiovascular Disease, Gastroenterology. 135:6 pp. 1935-1944.
3 Koskinen J, Magnussen CG, Kähönen M, Loo B, Marniemi J, Jula A, Saarikoski LA, Huupponen R, Viikari SA, Raitakari OT and M Juonala 2012, Association of liver enzymes with metabolic syndrome and carotid atherosclerosis in young adults. The Cardiovascular Risk in Young Finns Study, Annals of Medicine. 44:2 pp. 187-195.
4 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.
5 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.