Alanine Aminotransferase: What Your Results Mean
Bottom line: ALT is a liver enzyme. Normal is 5-40 U/L. High ALT may indicate liver damage or inflammation.
What Is Alanine Aminotransferase (ALT)?
Alanine aminotransferase (ALT), also known as serum glutamate-pyruvate transaminase (SGPT), is an enzyme primarily found in the liver. It plays a crucial role in the metabolism of amino acids, specifically alanine. When liver cells are damaged or inflamed, ALT is released into the bloodstream. Therefore, measuring ALT levels in the blood is a common way for healthcare providers to assess the health of your liver.
An elevated ALT level can indicate that your liver is under stress or has been injured. This damage could be due to various reasons, including viral infections like hepatitis, alcohol abuse, certain medications, fatty liver disease, or other liver conditions. By monitoring ALT levels, doctors can help diagnose liver problems, track the progression of liver disease, and assess the effectiveness of treatments.
Alanine Aminotransferase (ALT) Reference Ranges
| Classification | Range (U/L) |
|---|---|
| Very Low | 0 - 5 |
| Low | 6 - 10 |
| Normal | 11 - 40 |
| Moderately High | 41 - 100 |
| Significantly High | 101 - 500 |
| Extremely High | > 500 |
What Affects Your Alanine Aminotransferase (ALT) Levels?
- Liver disease (e.g., hepatitis, cirrhosis)
- Alcohol consumption
- Certain medications (e.g., statins, acetaminophen)
- Non-alcoholic fatty liver disease (NAFLD)
- Muscle injury or strenuous exercise
- Celiac disease
- Hemolysis (breakdown of red blood cells)
- Obesity
When to Get Tested
Your doctor may order an ALT test as part of a routine physical examination, especially if you have risk factors for liver disease. It's commonly included in liver function panels to screen for liver damage or to investigate symptoms such as jaundice (yellowing of the skin and eyes), abdominal pain, fatigue, or nausea. If you have a known liver condition, ALT levels may be monitored regularly to track its progression and the effectiveness of your treatment.
Look Up Your Alanine Aminotransferase (ALT) Result
Select your value below to see a detailed breakdown of what it means:
Read the Full Blood Test Guide
Frequently Asked Questions
Not necessarily. While a significantly elevated ALT can indicate serious liver damage, mild elevations can sometimes be caused by less severe factors like certain medications, strenuous exercise, or even a fatty liver that is not yet causing significant harm. Your doctor will interpret the ALT result in the context of your overall health and other tests.
Yes, in many cases, ALT levels can return to normal if the underlying cause of the liver irritation is addressed. For example, if elevated ALT is due to a medication, stopping that medication might allow liver enzymes to normalize. If it's due to an infection like viral hepatitis, treatment and recovery can lead to normalized ALT levels.
Normal ALT reference ranges can vary slightly between laboratories, but generally for adults, they are typically between 11 and 40 U/L. It's important to discuss your specific lab results with your healthcare provider, as they will interpret them based on your individual health profile and the laboratory's specific reference range.
