Know Your Blood Parameter : ALT (SGPT)
- Summarised by TGHC Editorial Team
- May 25, 2025
- 3 min read
Updated: Dec 29, 2025
Parameter Name
Alanine Aminotransferase (ALT / SGPT)
Alanine Aminotransferase, commonly referred to as ALT or SGPT (serum glutamate-pyruvate transaminase), is an enzyme primarily found in the liver. It plays a crucial role in the metabolism of amino acids, specifically in the conversion of alanine and alpha-ketoglutarate to pyruvate and glutamate. The presence of this enzyme in the bloodstream is typically low, and its levels can be indicative of liver health.
Test Type
Blood
The ALT test is a blood test that measures the amount of alanine aminotransferase in the blood. A healthcare provider usually collects a blood sample from a vein in your arm, and the sample is then sent to a laboratory for analysis. This test is often part of a liver function panel that evaluates various enzymes and substances associated with liver health.
Normal Range
Men: 10 – 40 U/L
Women: 7 – 35 U/L (May vary slightly by lab)
The normal range for ALT levels can vary based on several factors including age, sex, and the specific methodologies used by different laboratories. It is important to interpret ALT results in conjunction with other liver function tests and clinical findings.
High Levels Indicate
High levels of ALT typically indicate liver cell damage or inflammation. This elevation can be seen in various conditions such as viral hepatitis, fatty liver disease (both alcoholic and non-alcoholic), liver cirrhosis, drug-induced liver injury, and certain metabolic disorders. In some cases, elevated ALT levels can also suggest issues outside the liver, such as muscle injury or heart disease, necessitating further investigation.
Low Levels Indicate
Low levels of ALT are generally not a cause for concern. In fact, very low levels may occasionally occur in individuals with vitamin B6 deficiency, as this vitamin is essential for the proper functioning of the enzyme. However, such low levels are rarely clinically significant and do not typically warrant any specific treatment unless accompanied by other symptoms or abnormal test results.
Why It's Tested
The ALT test is performed to assess liver health, detect liver damage or inflammation, and monitor the progression of liver diseases. It is often ordered when a patient presents with symptoms suggestive of liver dysfunction, such as jaundice, abdominal pain, or unexplained fatigue. Additionally, it may be used to monitor the effects of medications that can impact liver function.
Associated Symptoms (if abnormal)
When ALT levels are abnormal, particularly elevated, patients may experience various symptoms related to liver dysfunction. Common symptoms include fatigue, jaundice (yellowing of the skin and eyes), abdominal pain or discomfort, nausea, vomiting, and dark urine. In some cases, there may also be pale stools, itching, and swelling in the abdomen or legs, indicating a more severe liver condition.
What To Do If Abnormal
If ALT levels are found to be abnormal, it is crucial to follow up with additional testing. This may include repeating the ALT test, correlating results with aspartate aminotransferase (AST) and other liver enzymes to assess the extent of liver damage. An abdominal ultrasound may be recommended to visualize the liver and detect any structural abnormalities. Consulting a healthcare provider is essential for interpreting results and determining the appropriate next steps based on individual health circumstances.
Common Conditions Related
Several common medical conditions are associated with elevated ALT levels. These include fatty liver disease, which can be caused by alcohol consumption or metabolic syndrome; various forms of hepatitis (A, B, C) which are viral infections that lead to liver inflammation; cirrhosis, a late-stage scarring of the liver; and drug-induced liver injury, which can occur due to certain medications or toxins. Understanding these conditions is vital for appropriate diagnosis and management.
Nutrition or Lifestyle Connection
To promote liver health and potentially lower ALT levels, individuals are encouraged to adopt certain lifestyle and dietary changes. This includes reducing alcohol intake, which can significantly impact liver function. Maintaining a healthy weight through regular physical activity and a balanced diet is also crucial. Incorporating liver-friendly foods such as leafy greens, turmeric, and omega-3 fatty acids while avoiding processed foods high in sugars and unhealthy fats can support liver health. Additionally, regular check-ups with healthcare providers can help monitor liver function and overall health.
References (APA Format)
Mayo Clinic. (2023). Liver function tests.
MedlinePlus. (2023). Alanine transaminase (ALT) test.
American Liver Foundation. (2023). Understanding liver tests.
