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Alanine Aminotransferase (ALT) Unit Converter
Alanine Aminotransferase (ALT), formerly known as Serum Glutamic Pyruvic Transaminase (SGPT), is an enzyme found primarily in the liver and kidney. It catalyzes the transfer of an amino group from L-alanine to alpha-ketoglutarate, producing pyruvate and L-glutamate. This reaction is a critical step in the glucose-alanine cycle, allowing muscle tissues to send nitrogen to the liver for urea processing.
Clinically, ALT is the most specific biomarker for hepatocellular injury. Unlike Aspartate Aminotransferase (AST), which is abundant in heart and skeletal muscle, ALT is concentrated mainly in the liver parenchyma. When liver cells are damaged (e.g., by viral hepatitis, drugs, or ischemia), ALT leaks into the bloodstream, causing serum levels to rise. While the standard reporting unit is U/L (International Units per Liter), the SI system uses katals (µkat/L). This converter allows precise switching between these enzyme activity standards.
SI Units
RecommendedMicrokatals per liter (Standard International).
Conventional Units
Clinical Context
ALT levels are interpreted in the context of the clinical history. Mild elevations (2–5x normal) are common in non-alcoholic fatty liver disease (NAFLD) and chronic viral hepatitis. Marked elevations (>15x normal) suggest acute necrosis, such as in acetaminophen toxicity or acute viral hepatitis.
The De Ritis Ratio (AST/ALT) is often used to narrow the differential diagnosis. An AST/ALT ratio > 2.0 is suggestive of alcoholic liver disease, while a ratio < 1.0 is more typical of viral hepatitis or NAFLD. Reference ranges vary but are generally 7–56 U/L. The conversion factor is constant: 1 U/L ≈ 0.0167 µkat/L.
Clinical References
How to Use This Calculator
Follow these steps to get accurate clinical conversions instantly.
Enter Values
Input your laboratory results into the corresponding unit field (e.g., U/L). You can use either dot or comma decimals.
Automatic Conversion
The calculator works in real-time. As you type in one field, all other units (like µkat/L) are instantly updated.
Verify Units
Check the SI Units section for the internationally recommended reporting standard (µkat/L).
Reset
Use the Clear button to reset all fields before starting a new calculation.
Frequently Asked Questions & Tips
ALT is an enzyme. Clinical labs measure its catalytic activity, not its weight. Therefore, units like U/L or katals are used instead of mg/dL.
Yes, in this context, U/L (Units per Liter) and IU/L (International Units per Liter) are interchangeable.