Comprehensive Analysis of Liver Function Tests: 6 Key Indicators You Must Know

 

The liver plays a crucial role in metabolism, detoxification, and storage in the human body. Liver diseases are often insidious and difficult to detect in their early stages. If there is a problem with the liver, the first signs will usually appear in liver function test indicators.

 

Six Key Indicators in Liver Function Tests

Liver function test results primarily focus on the following six indicators. If abnormalities are detected, it may indicate liver issues, and medical attention should be sought promptly.

Bilirubin

Bilirubin is a byproduct of red blood cell breakdown, metabolized and excreted mainly by the liver. It is categorized into total bilirubin and direct bilirubin. The levels of these bilirubins reflect the liver's ability to metabolize and excrete bilirubin.

Elevated bilirubin levels may indicate liver cell damage, bile duct obstruction, or hemolysis. Conditions such as jaundice hepatitis, bile duct infections, and gallstones can all lead to increased bilirubin levels.

Total Protein, Albumin, and Globulin

These proteins are primarily synthesized by the liver, and their levels reflect liver synthesis function and nutritional status.

• Reduced total protein and albumin levels may be associated with chronic liver disease and liver cirrhosis.
  
• The albumin/globulin ratio is also an important reference indicator. A decrease may suggest chronic hepatitis, cirrhosis, or liver cancer.
  
• Elevated globulin levels may indicate infections, autoimmune diseases, or progressive liver disease.
  

Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST)

These two transaminases are mainly found inside liver cells. When liver cells are damaged, these enzymes are released into the bloodstream.

Elevated levels of ALT and AST in the blood usually indicate liver cell damage, which may suggest hepatitis, cirrhosis, or liver cancer. Long-term drug abuse, excessive alcohol consumption, and other factors can also cause liver cell damage, leading to increased transaminase levels.

Alkaline Phosphatase (ALP) and Gamma-Glutamyl Transferase (GGT)

These two enzymes are primarily involved in bile acid metabolism, and their levels reflect bile flow within the liver.

Elevated ALP and GGT levels may indicate bile duct obstruction, hepatitis, cirrhosis, or liver cancer. Additionally, bile duct infections and gallstones may also cause significant increases in these enzymes.

Cholinesterase (ChE)

Cholinesterase is an enzyme that reflects the liver’s synthetic function. The more severe the liver damage, the lower the cholinesterase level. A decline in cholinesterase levels may indicate impaired liver synthesis function.

Adenosine Dehydrogenase (ADA)

Adenosine dehydrogenase is associated with the activity and severity of liver disease. In cases of acute hepatitis, ADA levels may be mildly elevated, whereas in severe hepatitis, ADA levels may rise significantly.

 

Seven Precautions Before a Liver Function Test

• Get Enough Sleep: Maintaining good sleep habits is crucial for liver health. Ensure adequate sleep before a liver function test to avoid fatigue, which could affect liver function results.
  
• Fast Before Testing: Fasting helps prevent food intake from affecting liver function indicators, ensuring accurate test results. It is recommended to fast for 8–12 hours before the test. Drinking small amounts of water is acceptable, but excessive water intake, especially sugary or caffeinated beverages, should be avoided.
  
• Adjust Your Diet: Avoid overly greasy, spicy, or irritating foods a few days before the test. These foods can elevate blood lipid levels and affect the accuracy of test results.
  
• Avoid Alcohol: Alcohol directly damages the liver. Strictly avoid alcohol before a liver function test, as long-term or excessive drinking can cause liver function abnormalities and interfere with test results.
• Inform Your Doctor About Medications: Before the test, inform your doctor about any medications you are taking, including prescription drugs, over-the-counter medications, and supplements. Some drugs may affect liver function and cause abnormal test results. Your doctor may advise pausing certain medications before the test.
• Avoid Getting Sick: If you catch a cold before the test, it is best to wait until you have fully recovered for at least seven days before taking the test. A cold may affect liver function test results, leading to misdiagnosis or missed diagnoses.
• Avoid Strenuous Exercise: Refrain from intense exercise or excessive physical exertion before the test, as such activities may cause muscle damage, affecting liver function indicators. It is advisable to rest and stay relaxed before the test.

 

How to Handle Common Liver Function Abnormalities

How to Respond to Elevated Bilirubin Levels?

Elevated bilirubin levels can be caused by excessive production, liver disease, or bile duct obstruction. If bilirubin levels are high, it is recommended to consult a gastroenterologist for further evaluation.

If elevated bilirubin is accompanied by yellowing of the eyes and skin, anemia, abdominal pain, vomiting, fatigue, fever, or pale-colored stools, it may indicate acute hepatitis, bile duct obstruction, or hemolytic disease. Immediate medical attention is required, along with blood tests, ultrasound, MRI, or CT scans to diagnose the underlying issue. In clinical practice, severe liver diseases often present with both elevated transaminase and abnormal bilirubin levels, necessitating urgent medical evaluation.

How to Address Elevated Transaminase Levels?

If transaminase levels are elevated, seek medical attention promptly to determine the cause of liver function abnormalities and receive targeted treatment.

For example, if elevated transaminase levels are accompanied by obesity, high blood lipids, high uric acid, or high blood sugar, an ultrasound should be conducted to check for fatty liver disease.

Liver function abnormalities caused by fatty liver can often be managed by dietary control and moderate exercise to reduce weight. In most cases, liver function returns to normal with proper care. However, if transaminase levels are significantly elevated, acute viral hepatitis or other serious conditions should be ruled out.

 

FAQs about Liver Function

How to Increase Liver Function?

To enhance liver function, it is essential to maintain a healthy lifestyle by adopting balanced eating habits, engaging in regular physical activity, and minimizing exposure to harmful substances. A nutrient-rich diet that includes plenty of fruits, vegetables, whole grains, and lean proteins supports liver health, while avoiding excessive processed foods, sugars, and unhealthy fats helps reduce liver strain. Regular exercise improves blood circulation and helps maintain a healthy weight, preventing conditions like fatty liver disease. Limiting alcohol consumption and reducing exposure to toxins, such as environmental pollutants and unnecessary medications, can also protect liver cells from damage. Additionally, staying well-hydrated supports the liver’s detoxification processes, and getting sufficient sleep allows the body to repair and regenerate, ensuring optimal liver function. 

What Foods are Good for Liver Function?

Blueberries & Cranberries: Rich in antioxidants, may reduce fatty liver and inhibit cancer cells.  

Coffee: Protects the liver, reduces disease risk, and increases antioxidants.  

Beetroot Juice: Contains antioxidants that may reduce liver inflammation.  

Tea: Green tea may lower liver enzymes and cancer risk but requires caution.  

Grapefruit: Contains antioxidants that reduce inflammation and fibrosis.  

Fatty Fish: High in omega-3s, reduces liver fat, and fights inflammation. 

Grapes: May reduce inflammation and oxidative damage, but more studies are needed.  

Prickly Pear: May help protect against alcohol toxicity and support liver health.  

Nuts: Rich in healthy fats and antioxidants, linked to lower NAFLD risk.  

Olive Oil: Helps reduce liver fat and improves metabolic health.  

Cruciferous Vegetables: Support detoxification and may lower fatty liver risk.  

Can Antibiotics Affect Liver Function Test?

Yes, antibiotics are a common cause of drug-induced liver injury (DILI), which can significantly affect liver function tests. Certain antibiotics, such as amoxicillin-clavulanate, rifampin, isoniazid, and macrolides, have been associated with hepatotoxicity, leading to elevated liver enzymes, cholestasis, or even acute liver failure in severe cases.

Can Stress Affect Liver Function Tests?

Yes, stress can affect liver function tests by causing elevated enzyme levels. When the body experiences stress, it releases stress hormones like cortisol and adrenaline, which can trigger inflammation and impact liver function. Studies suggest that chronic stress and anxiety may lead to increased levels of liver enzymes such as alanine aminotransferase (ALT) and aspartate aminotransferase (AST), which are markers of liver cell damage.

 

 

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