Blood and lab tests
What Is ALT on a Blood Test? Liver Enzyme
ALT (Alanine Aminotransferase) · say it: ay-el-TEEAlso written: alanine aminotransferase, SGPT, ALAT
Short answer
ALT is an enzyme found mainly in the liver; when liver cells are irritated or damaged, more ALT leaks into the blood.
What it means
Enzymes are proteins that help chemical reactions happen in the body. ALT does most of its work inside liver cells, with small amounts elsewhere.
When liver cells are stressed or injured, they release ALT into the bloodstream, so a raised ALT is one sign that the liver may be affected. Common causes range from fatty liver and alcohol to infections and some medicines.
ALT is part of a group of tests often called liver function tests or a liver panel. Doctors usually interpret it together with AST, bilirubin and other results, and they look at how high it is and whether it changes over time.
Where you may see it
- Liver function tests or hepatic panels
- Comprehensive metabolic panels
- Monitoring for some long-term medicines
📄 How it looks on a report
ALT 52 U/L H
🙅 What it does not mean
- A raised ALT does not tell you the cause; it only shows that the liver may be irritated.
- A mildly raised ALT is common and does not automatically mean serious liver disease.
- A normal ALT does not rule out every liver condition.
🗒️ Questions to ask your doctor
🧾 Reports where you will see “ALT (Alanine Aminotransferase)”
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💊 Medicines whose labels mention “ALT (Alanine Aminotransferase)”
Plain-English explanations of each medicine, from its official FDA label.
- Divalproex Sodium
An anti-epileptic (anti-seizure) drug of the valproate type. The label also uses it to treat manic episodes of bipolar disorder and to prevent migraine headaches.
- Isoniazid
An antibacterial medicine of the antimycobacterial type, used against tuberculosis bacteria
- Ondansetron
A serotonin-3 receptor antagonist, a medicine that blocks serotonin 5-HT3 receptors to help prevent nausea and vomiting
🔗 Read more from trusted sources
- “ALT (Alanine Aminotransferase)” on MedlinePlus ↗
US National Library of Medicine
- NCI Dictionary definition ↗
US National Cancer Institute: “sgpt”
- MedlinePlus lab test guides ↗
US National Library of Medicine
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