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The Union Health Ministry has advised people to monitor Alanine Aminotransferase (ALT) levels as an early indicator of liver injury, highlighting the importance of routine liver health screening.

What is Alanine Aminotransferase (ALT)?

• Alanine Aminotransferase (ALT), also known as Serum Glutamic-Pyruvic Transaminase (SGPT), is an enzyme found mainly inside liver cells (hepatocytes), with smaller amounts present in muscles and the heart.
• It plays an important role in amino acid metabolism, helping convert amino acids into energy required for normal body functions.
• Normally, only small amounts of ALT circulate in the bloodstream. When liver cells are damaged due to inflammation, infection, or injury, ALT leaks into the blood, making it one of the earliest laboratory markers of liver injury.

Why is ALT Important?

ALT is a sensitive indicator of ongoing liver damage and forms an important part of the Liver Function Test (LFT). Elevated ALT levels may indicate liver disorders such as:

• Viral hepatitis (Hepatitis B & C)
• Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD)
• Alcohol-related liver disease
• Autoimmune hepatitis
• Drug-induced liver injury

However, raised ALT alone does not confirm liver disease, as the enzyme is also present in other tissues. Further clinical evaluation and investigations are required.

Limitations of ALT Testing

Although ALT is an important screening marker, normal ALT values do not rule out liver disease.

People with MASLD may have normal or only mildly elevated ALT despite significant liver damage. Similarly, in advanced liver cirrhosis, ALT levels may return to normal because very few healthy liver cells remain to release the enzyme.

Therefore, ALT should always be interpreted along with other liver function tests and clinical findings.

Who Should Undergo ALT Testing?

• ALT testing is performed through a simple blood test and is routinely included in comprehensive health check-ups.
• Annual testing is generally sufficient for healthy adults. More frequent monitoring is recommended for people with:Obesity, Diabetes, High cholesterol, Thyroid disorders, Viral hepatitis, Long-term medication use, Alcohol consumption, Family history of liver disease, and Sedentary lifestyle