There are a number of liver function tests, with lots of complex names. Alanine transaminase (ALT) test. ALT is an enzyme that helps break down proteins and is found mainly in your liver. High levels in your blood could mean you have liver damage. Alkaline phosphatase (ALP) test. ALP is an enzyme you have in your liver, bile ducts, and bone. You might have high levels if you have liver damage or disease, a blocked bile duct, or bone disease. Albumin and total protein test.