This test usually consists of up to six separate elements – the results of which will assist in diagnosis. However, the term "liver function test" is misleading, because it can measure possible hepatocellular damage (temporary or permanent), rather than liver function.
The LFT should consist of all of the following:
Alanine aminotransferase (ALT)
Aspartate aminotransferase (AST)
Albumin
Gamma-glutamyl transferase (GGT)
Bilirubin
Alkaline phosphatase (ALP)
The reference ranges for these tests are not standardised, which means that each laboratory may have contrasting reference ranges, due to the analysers they use.
It is therefore important that you only compare your results in correlation to the reference ranges provided alongside your results. If you have some results from a previous test, and analysed at a different laboratory, you will probably notice that the reference ranges aren’t exactly the same.
So, you should never look at the results of one test, and then the reference ranges of another.
If some of the results fall outside the reference range, it doesn’t necessarily indicate that you have a liver problem, but further tests should be called to determine what has caused the ‘abnormal’ result.
There are many, many reasons and causes as to ‘why’ some of the results don’t fall within their reference ranges, and it is up to the Health Professional to decide what further action needs to be taken.
Because some of the enzymes such as alanine aminotransferase, aspartate aminotransferase, and gamma-glutamyl transferase, are found in other organs apart from the liver, it could be that the cause of some abnormal blood results are due to a problem with e.g. the heart, or the kidneys, rather than the liver.
It is also important to understand that the liver can become inflamed due to e.g. an injury to the body, medication, and an infection anywhere in the body. In the case of the latter, once the infection has left the body, the liver inflammation will subside. N.B The alanine aminotransferase levels increase when the liver is inflamed.
Interpreting results from a LFT can be quite a challenge, and sometimes it may be necessary to undertake many other blood tests to establish the root cause of the problem - meaning that the diagnosis is often made after a long process of elimination.
If you have any concerns over your results, then I would advise you to speak further to your Health Professional, or if you have any general questions regarding the LFT, please feel free to contact me - either through HealthUnlocked or at: sarah.tattersall@liver4life.org.uk