After having the tests done, there should be some level of concern if the reading is high. The liver could be extremely damaged and therefore prone to diseases that could be life threatening. If you are doing something that could be causing the disease, such as drinking and taking illegal drugs, then stopping before it is too late and receiving treatment will ensure that your life will not be in danger.
However, if you are fit and healthy with a high ALT (GPT) reading, you should go through your family history of illness and disease to see if there is any possibility that it has been somewhat genetic from previous generations. If this is the case you will need to have treatment to stop or help prevent the disease harming you any further. It is more difficult this way as there is no direct cause for it to happen; if someone drinks too much then stopping the drink and having treatment will allow the liver to mend itself quicker if there is not too much damage.
Considering rehabilitation treatment if long-term alcohol consumption means that you are at risk of diseases such as cirrhosis of the liver can be essential. These residential treatments can allow you to reclaim the life skills and the confidence needed to live a sober and healthy life.