SGPT/ALT (Alanine Amino-Transferase) – BC285
Liver Function TestReport: Same Day
Sample Type: Blood (Serum)
Test Code: BC285
The SGPT/ALT (Alanine Aminotransferase) test measures the level of the ALT enzyme in your blood. ALT is found predominantly in the cells of the **liver**. When the liver is damaged, ALT is released into the bloodstream, making this test a highly **specific indicator of liver injury**.
✔ A fundamental component of the Liver Function Test (LFT) panel.
✔ A key marker for detecting liver damage from hepatitis, medications, alcohol, or fatty liver disease.
✔ Helps monitor the progression of liver disease and response to treatment.
✔ Often interpreted alongside AST (SGOT) levels.
ALT: A Specific Signal from Your Liver
Alanine Aminotransferase (ALT), historically known as Serum Glutamic-Pyruvic Transaminase (SGPT), is an enzyme primarily involved in protein metabolism within liver cells (hepatocytes). Unlike AST (SGOT), which is found in significant amounts in the heart and muscles as well, ALT is present in much higher concentrations in the liver compared to other tissues.
This relative liver-specificity makes the ALT test particularly valuable. When liver cells are damaged for any reason—be it viral infection (hepatitis), toxins (alcohol, certain drugs), fatty infiltration, or lack of blood flow—the cell membranes become leaky, and ALT spills out into the bloodstream. A rise in blood ALT levels is therefore a direct signal of ongoing liver cell injury.
Interpreting Elevated ALT Levels
An elevated ALT level prompts your doctor to investigate the underlying cause of liver stress or damage:
- Mild Elevation: Can be seen in chronic conditions like fatty liver disease or chronic viral hepatitis.
- Moderate to High Elevation: Often indicates more acute liver damage, such as acute viral hepatitis, significant alcohol injury, or damage from certain medications or toxins.
- Very High Elevation (often >10 times the upper limit): Usually suggests extensive acute liver damage, potentially due to viral hepatitis, drug toxicity, or ischemic hepatitis (lack of oxygen to the liver).
As mentioned previously, the **AST/ALT ratio** is also a critical factor. In most liver conditions causing cell damage (like viral hepatitis), ALT rises higher than AST. However, in alcoholic liver disease, the pattern is often reversed, with AST being significantly higher than ALT.
Frequently Asked Questions (FAQ)
It measures the level of the enzyme Alanine Aminotransferase (ALT) in your blood. ALT is primarily found in liver cells, so this test is a specific indicator of liver health.
While both are "liver enzymes," AST is also found in significant amounts in the heart, muscles, and other tissues. ALT is much more concentrated in the liver. Therefore, an elevated ALT level is more likely to point specifically to a liver problem.
A high ALT level is a sign of liver cell damage or inflammation. Common causes include viral hepatitis (like Hepatitis A, B, or C), fatty liver disease, alcohol use, certain medications, or other liver conditions.
If AST is elevated but ALT is normal or only slightly raised, it suggests the source of the enzyme release might be outside the liver, possibly from the heart (e.g., after a heart attack) or muscles (e.g., after strenuous exercise or injury).
While not strictly necessary for ALT alone, this test is almost always part of a Liver Function Test (LFT) panel. Fasting (8-12 hours) is recommended for the LFT panel to ensure the accuracy of other components like bilirubin and proteins. Always follow your doctor's or the lab's specific instructions.