What should you know about an ALT blood test?

ALT is found mainly inside liver cells. When those cells are irritated, ALT can enter the bloodstream. A result on its own does not identify one diagnosis or show how well the liver is working. Clinicians consider the laboratory range, other liver markers, symptoms, alcohol use, weight, recent illness and medicines or supplements.

Raised ALT may occur with liver inflammation, fatty liver changes, viral illness or medication effects. It can also be temporary. Blood tests may be used while assessing conditions such as Anaemia, Brucellosis, Chronic Fatigue Syndrome, Chronic Kidney Disease, Coeliac Disease, Crohn's Disease, Dengue Fever or Glandular Fever, but an ALT result does not prove any of these conditions.

Ask the clinician who ordered the test to explain the result beside the laboratory range and your other findings. Provide a complete list of prescription medicines, non-prescription products and supplements. Do not stop a prescribed medicine without advice. Follow any plan for a repeat sample, ultrasound or additional blood tests, and avoid alcohol until you have received personalised guidance if liver irritation is suspected.

Arrange prompt medical review for yellowing of the skin or eyes, dark urine, pale stools, persistent vomiting, marked abdominal swelling, confusion, unusual bleeding, or severe right-sided upper abdominal pain. These symptoms need assessment regardless of whether an ALT result is available.

Ask what your ALT means alongside the other liver tests, whether a repeat sample is needed, which medicines or supplements could affect it, and whether imaging or specialist review is appropriate.