Final answer:
The gamma glutamyl transpeptidase (GGT) test is the most specific test to diagnose liver dysfunction.
Step-by-step explanation:
One of the most specific tests to diagnose liver dysfunction is the gamma glutamyl transpeptidase (GGT) test. It is a sensitive marker for cholestatic damage and can help identify the cause of an isolated elevation in alkaline phosphatase (ALP). GGT levels can be elevated even with minor levels of liver dysfunction and are commonly raised in alcohol toxicity.