Lab marker · High

High Alanine Aminotransferase (ALT): what it means

A Alanine Aminotransferase (ALT) result above the normal range is considered high. Here is what a raised Alanine Aminotransferase (ALT) can point to, and when it is worth discussing with a doctor.

Reference range: Approximately 7–40 U/L; lab-specific

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What a high Alanine Aminotransferase (ALT) can mean

  • Non-alcoholic fatty liver disease (NAFLD) — by far the most common cause in developed countries.
  • Viral hepatitis — A/B/C/E.
  • Alcohol-related liver disease — classically AST > ALT, but ALT also rises.
  • Drug-induced liver injury — acetaminophen overdose, statins (rare), antibiotics, supplements (especially green-tea extract, kava).
  • Autoimmune hepatitis, hemochromatosis, Wilson's disease — less common, worth excluding when ALT is high without obvious cause.

When to discuss with a doctor

ALT >3× the upper reference limit, or any persistent elevation, warrants a primary-care visit and follow-up labs (AST, GGT, alkaline phosphatase, bilirubin, viral hepatitis serology, abdominal ultrasound). ALT >1000 U/L is acute liver injury and needs same-day evaluation. Mediora.AI flags critical values inside your report.

Conditions this can relate to

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Mediora.AI is informational - interpretation, not a diagnosis. A single out-of-range value is common and often benign; always discuss decisions with your doctor.