Lab marker · Low

Low Alanine Aminotransferase (ALT): what it means

A Alanine Aminotransferase (ALT) result below the normal range is considered low. Here is what a reduced 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 low Alanine Aminotransferase (ALT) can mean

  • Vitamin B6 deficiency — ALT requires pyridoxal phosphate as cofactor.
  • Severe end-stage liver disease — few remaining hepatocytes left to release the enzyme.
  • Most low ALT readings are benign and don't need investigation.

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.