What should you know about liver function test ranges?

A reference interval is a guide based on the laboratory method; it is not a personal boundary between health and illness. Results just outside it may not have the same meaning as a marked or changing result, and a result inside it cannot exclude every liver or bile-duct problem. ALT, AST, ALP, GGT, bilirubin, albumin and clotting tests each describe different processes.

Compare your result only with the interval printed beside it, because methods vary. Your clinician also considers age, pregnancy where relevant, symptoms, medicines, supplements, alcohol, recent infection and previous blood tests. Hepatitis A, Hepatitis B, Hepatitis C and alcohol-related harm are possible topics for assessment when the overall picture supports them.

Do not compare your result with a friend’s report or an online chart. Bring the report to the clinician who requested it and ask what the flagged values mean together. Check whether you needed fasting or any other preparation, and disclose all treatments and supplements. Follow-up may involve observation, a repeat panel or targeted assessment.

Seek prompt care for yellowing eyes or skin, dark urine, pale stools, severe abdominal pain, persistent vomiting, confusion, unusual sleepiness or unexplained bleeding. Do not wait for a routine review if these symptoms are severe, sudden or getting worse.

Which laboratory interval applies to my result? Is the change isolated or part of a pattern? Could preparation, medicine, supplement or recent illness affect it? When should I repeat the test?