1 January 2004

Australian contribution to 'alcohol markers' supplement of "Addiction".

Traditional markers of excessive alcohol use. Conigrave KM, Davies P, Haber P, Whitfield JB. Addiction (2003) 98 (Suppl.2) 31-43

Dear Colleagues,

This is an excellent Australian contribution to the important issue of documenting alcohol use in a quantitative way. Although the markers are over a generation old, their scientific basis is often forgotten. This article gives us the ‘how and why’ on the liver-related blood tests: ALT (alanine amino-transferase); AST (aspartate amino-transferase) and GGT (gamma glutamyl-transaminase) [collectively called “transaminases”] and the red blood cell volume (‘mean corpuscular volume’ ‘MCV’ or red cell size). These are all commonly used both as screening tools as well as prognostic indicators in established liver disease.

The authors use a Medline search of the thousands of studies on alcohol related disease in order to systematically examine the specificity and sensitivity of each test.
Simple blood tests will also show the INR (clotting index or ratio) and platelet count (thrombocytes) which are just as ‘traditional’ and most usually affected in severe alcohol use with associated liver disease. Thus they might be seen as ‘secondary’ markers of excessive alcohol use and are not covered by these authors.

As well as self-report on clinical interview, other items in this ‘Addiction Supplement’ cover numerous other aspects of tests pointing towards alcohol use and liver disease. These include carbohydrate deficient transferrin, serum sialic acid, beta hexosamine, ethyl glucuronide and 5-hydroxytryptophol … as well as the direct measurement of ethyl alcohol itself in serum, urine and other body fluids (Robert Swift, p73).

I often tell students that the raw GGT tells us how many standard drinks that the individual patient consumes in a month. Try it yourself! Divide the GGT by 31 and ask your next few patients their average consumption. It is often closer to the truth than comfort for the drinking patient, although it is unhelpful in established cirrhosis. Like other ‘rules-of-thumb’ this could also be misleading and so must be taken in context with history, physical examination and other clinical factors (palmar erythema, spider nævi, bruising, jaundice, etc). Either way, such discussions could be an interesting and productive starting point for a serious discussion about drinking levels.

Highly recommended reading from these experienced Sydney University experts.

comments by Andrew Byrne ..