You mean does not include?
The Hawaiian study is just one of such studies. The examination of kava's health effects on the Aboriginal population reached a similar conclusion. Apparently (perhaps
@kasa_balavu can clarify this), many Fijian doctors are also aware of the link between *slightly* higer GGT levels and kava consumption and do not seem to consider it as an indicator of any health problems (especially as it appears to be reversible). From what I understand, GGT levels can increase in response to lots of factors and do not in themselves indicate liver injury. E.g. a person who never drinks alcohol will likely have high GGT levels if he or she drinks some alcohol within 24h before the test. The test will show higher GGT in response to alcohol intake, but it will obviously not mean that this person's liver is in some serious trouble. I suppose this is the main reason why most liver tests in the USA do not include GGT. But note that I am not a medical professional, so I am not sure if my take on this is accurate.