What does an aspartate aminotransferase (AST) level of 45 indicate?

Dec 03, 2025 Source: Cainiu Health

Dr. Gao Jun

Introduction

Aspartate aminotransferase (AST) level of 45 U/L is slightly above the normal upper limit of 40 U/L. This may be caused by overexertion, alcohol consumption, fatty liver, viral hepatitis, cholecystitis, or other conditions. Improvement can be achieved through rest, abstaining from alcohol, dietary adjustments, and medication. If the levels continue to rise or are accompanied by discomfort in the liver area or jaundice, prompt medical attention is necessary.

Aspartate aminotransferase (AST) at 45 U/L is slightly above the normal upper limit of 40 U/L. This may be caused by overexertion, alcohol consumption, fatty liver, viral hepatitis, cholecystitis, or other conditions. Improvement can be achieved through rest, abstaining from alcohol, dietary adjustments, and medication. If the levels continue to rise or are accompanied by discomfort in the liver area or jaundice, prompt medical attention is required.

1. Overexertion: Long-term熬夜, physical exhaustion can impair liver metabolism, leading to mild enzyme elevation. There may be no obvious symptoms or only mild fatigue. It is recommended to maintain regular作息 with 7–8 hours of sleep per night, avoid staying up late and overexertion, and get adequate rest to promote liver recovery.

2. Alcohol stimulation: Alcohol directly damages liver cells, increasing enzyme release, possibly accompanied by nausea and dull pain in the liver area. Immediate abstinence from alcohol and avoidance of all alcoholic beverages are advised. A light diet helps reduce the burden on the liver.

3. Fatty liver: High-fat diet and obesity lead to fat accumulation in liver cells, causing elevated enzymes, often accompanied by fatigue and a feeling of fullness or discomfort in the liver area. Patients may take medications such as polyene phosphatidylcholine capsules, silibinin capsules, or reduced glutathione tablets under medical supervision to improve symptoms.

4. Viral hepatitis: Hepatitis viruses invade liver cells, resulting in increased enzyme levels, along with loss of appetite, fatigue, and yellowing of the skin. It is recommended to take entecavir dispersible tablets, tenofovir disoproxil fumarate capsules, or diammonium glycyrrhizinate enteric-coated capsules under a doctor's guidance to relieve symptoms.

5. Cholecystitis: Inflammation of the gallbladder affects surrounding tissues, impairing bile excretion and indirectly damaging the liver, leading to elevated enzyme levels. Symptoms may include right upper abdominal pain and fever. Patients may follow medical advice to use anti-inflammatory and cholagogue tablets, cefixime dispersible tablets, or ursodeoxycholic acid capsules to alleviate symptoms.

Maintain a light diet rich in fresh fruits, vegetables, and high-quality protein. Reduce intake of high-fat, high-sugar, spicy, and irritating foods. Keep a regular作息, avoid staying up late, engage in moderate exercise to control body weight, avoid indiscriminate use of medications, and have regular follow-up tests to monitor liver function changes.

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Normal aspartate aminotransferase (AST), elevated alanine aminotransferase (ALT)—what does this indicate?

If the elevation is caused by physiological factors, it commonly occurs after recent sleep deprivation, excessive alcohol consumption, intense exercise, or taking certain medications. Alanine aminotransferase (ALT) is primarily present in the cytoplasm of hepatocytes; these factors can temporarily increase hepatocyte membrane permeability, leading to enzyme leakage into the bloodstream and thus elevated levels. However, they do not cause severe hepatocyte necrosis. Aspartate aminotransferase (AST), mainly located within mitochondria, therefore remains normal.