Quick Look

The liver primarily contains the enzyme alanine transaminase (ALT). Healthcare providers include an ALT blood test in liver panels and comprehensive metabolic panels to assess liver health. Elevated ALT levels in the blood may suggest liver damage and/or a liver condition.

Other Names

Alanine aminotransferase

SGPT

Serum glutamic-pyruvic transaminase

What is Alanine Transaminase (ALT) test?

Healthcare providers use this test to assess liver health because ALT levels can rise when the liver is damaged.

Healthcare providers do not rely solely on the ALT blood test for diagnosis since various liver problems can elevate ALT levels. Instead, they often include the ALT blood test in a comprehensive panel, such as liver function tests (LFT) or a comprehensive metabolic panel (CMP). These panels measure multiple aspects of your blood with one sample, offering more detailed information about your overall health.

When is the Alanine Transaminase test done?

Your healthcare provider may request a blood panel test, incorporating an ALT test, for screening, monitoring, or aiding in the diagnosis of liver conditions.

Screening

Screening involves checking for potential health issues before symptoms arise.

If you have risk factors for liver disease, such as heavy alcohol use, a family history of liver disease, diabetes, obesity, or injecting drugs with shared needles, your healthcare provider may recommend screening with a liver panel blood test, which includes an ALT test. 

Additionally, routine blood panel tests, like a comprehensive metabolic panel (CMP), often include ALT tests, even if you don’t have specific risk factors for liver disease.

Monitoring

For individuals with a liver condition, healthcare providers may order an ALT test, typically as part of a panel, to monitor whether the condition is improving, worsening, or remaining stable, with or without treatment. Monitoring may also include ALT tests and liver enzyme panel tests if you are taking medications that could impact liver health.

Diagnosing

In cases where signs and symptoms suggest possible liver problems, your provider may utilize an ALT test for diagnostic purposes. Although a diagnosis cannot be solely based on ALT levels, they play a crucial role in the diagnostic process.

Signs and Symptoms of Liver Conditions:

• Nausea and/or vomiting.
• Abdominal pain.
• Itchy skin.
• Jaundice (yellowing of the skin and eyes).
• Fatigue.
• Loss of appetite.

Test Preparation

• If your ALT test is included in a comprehensive metabolic panel (CMP), it is probable that you will be required to fast for 10 to 12 hours before undergoing the CMP blood test. Fasting entails refraining from consuming any food or beverages except water.

• While it is less typical, if you are exclusively undergoing an ALT blood test, fasting is not necessary.

• Regardless of the test type, your healthcare provider will provide specific instructions when ordering the bloodwork. It is essential to adhere to their directions carefully.

• Various medications and supplements have the potential to impact ALT levels, underscoring the importance of informing your healthcare provider about any drugs or dietary supplements you are currently taking before undergoing the test. In certain situations, your provider may recommend discontinuing a medication prior to the test, but it’s crucial to only do so if explicitly instructed by your provider.

• Additionally, it’s noteworthy that intense exercise can influence ALT levels. If you engage in rigorous physical workouts regularly, inform your healthcare provider before the ALT test to ensure an accurate interpretation of the results.

Normal Range of Results

The normal range for alanine transaminase (ALT) can vary among different laboratories. A commonly used reference range for an ALT blood test is 7 to 55 U/L (units per liter). It’s worth noting that ALT levels tend to be higher in individuals assigned male at birth compared to those assigned female at birth.

High Alanine Transaminase

Elevated levels of alanine transaminase (ALT) in your blood can result from damage or injury to liver cells, potentially indicating various conditions:

• Alcohol-induced liver injury.
• Fatty liver disease (accumulation of excess fat in the liver).
• Hepatitis (inflammation of the liver).
• Cirrhosis (scarring of the liver).
• Use of medications that are toxic to the liver.
• Liver tumor or liver cancer.
• Liver ischemia (insufficient blood flow to the liver, leading to liver tissue death).
• Hemochromatosis (excess iron in the body).
• Mononucleosis (“mono”).
• Certain genetic conditions affecting the liver.
• Although less common, elevated ALT levels can also suggest cell injury in other parts of the body, as ALT is not exclusively present in the liver.

It’s crucial to note that a high ALT test result does not necessarily indicate a medical condition. Less than 5% of individuals with elevated ALT levels have severe liver conditions. Other factors, such as additional blood test results and your medical history, will be considered by your healthcare provider when interpreting your results.

Low Alanine Transaminase

While having a lower-than-normal alanine transaminase (ALT) result is uncommon, it generally isn’t a major cause for concern. However, a lower-than-normal ALT level could potentially indicate a vitamin B6 deficiency or chronic kidney disease.

If your ALT result falls below the normal range, your healthcare provider will likely recommend retaking the test or undergoing additional testing to ensure there isn’t an underlying cause for the low level. Further investigation is important to rule out any potential health issues associated with a lower-than-normal ALT result.

Note

It’s important to understand that a high ALT level doesn’t automatically indicate a medical condition requiring treatment. Numerous factors can influence ALT levels, and it’s not uncommon for 1 in 20 healthy individuals to have results outside the normal range. Your healthcare provider will guide you on whether further tests are necessary to identify the underlying cause of the abnormal level. 

References

1. (N.d.). Retrieved from https://www.mayocliniclabs.com/test-catalog/overview/8362#Clinical-and-Interpretive 
2. professional, C. C. medical. (n.d.). Retrieved from https://my.clevelandclinic.org/health/diagnostics/22028-alanine-transaminase-alt