ALT (SGPT)
Alanine aminotransferase (ALT), also called SGPT, is an enzyme found primarily in the liver. When liver cells are damaged or inflamed, ALT leaks into the bloodstream, raising blood levels. ALT is the most liver-specific enzyme and is the first-line test for detecting liver injury from hepatitis, medications, alcohol, or fatty liver disease.
Reference Ranges
Male
7 – 56
U/L
Female
7 – 45
U/L
Child
7 – 40
U/L
Ages 1–18
Reference ranges may vary by laboratory. Always compare with the range printed on your lab report.
What Low Levels Mean
Low ALT is normal and not a cause for concern. Very low values are commonly seen in healthy individuals with no liver disease.
What High Levels Mean
Mildly elevated ALT (1–3x normal) is common in fatty liver disease (NAFLD), which affects up to 30% of Indians. Moderate elevation (3–10x) suggests hepatitis, medication injury, or alcohol damage. Very high ALT (>10x normal) indicates acute hepatitis, drug toxicity (paracetamol overdose), or acute liver failure.
Frequently Asked Questions
What is the difference between ALT and AST?
ALT is more specific to the liver — it's found mainly in liver cells. AST is found in the liver, heart, muscles, and kidneys. If both are elevated, it's likely liver-related. If AST is elevated but ALT is normal, the source may be heart or muscle damage.
Can exercise raise ALT?
Yes, intense exercise — especially weight training — can cause mild ALT elevation (1.5–2x normal) due to muscle breakdown. This is temporary and resolves within 1–2 days. If you exercise heavily, inform your doctor when interpreting liver function tests.
What is fatty liver disease?
Non-alcoholic fatty liver disease (NAFLD) is accumulation of fat in liver cells, not caused by alcohol. It's the most common cause of mild ALT elevation in India. Risk factors include obesity, diabetes, and metabolic syndrome. It can progress to cirrhosis if untreated. Weight loss and exercise are the primary treatment.
This information is for educational purposes only and should not replace professional medical advice. Always consult your doctor for interpretation of your test results.
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