A liver blood test is a collection of blood tests used to evaluate how well your liver is functioning. These tests measure different enzymes, proteins, and other substances produced by the liver to check for potential damage or disease. By assessing these levels, healthcare providers can identify liver inflammation, damage, or conditions like hepatitis, cirrhosis, or liver cancer.
Liver blood tests are critical because they can help detect liver problems early on, even before symptoms appear. Your liver is responsible for several essential functions, including detoxifying harmful substances, producing bile for digestion, and storing vitamins and minerals. When the liver isn’t working correctly, it can lead to serious health problems, so early detection through blood tests can be life-saving.
Typically, the liver function tests consist of:
ALT is an enzyme found in the liver that plays a crucial role in metabolism. High levels of ALT in the blood may indicate liver damage or inflammation, often linked to conditions like hepatitis or fatty liver disease.
Similar to ALT, AST is another enzyme that helps metabolize amino acids. Elevated AST levels can suggest liver damage, but AST is also found in the heart and muscles, so abnormal levels may also be linked to heart or muscle issues.
ALP is an enzyme related to the bile ducts. High levels of ALP can indicate blockages in the bile ducts or liver diseases, such as cirrhosis or hepatitis.
GGT is an enzyme that helps transport amino acids and peptides across cell membranes. Elevated GGT levels often indicate liver damage caused by alcohol abuse, certain medications, or other toxic substances.
Bilirubin is a substance produced during the normal breakdown of red blood cells. The liver processes bilirubin, and high levels in the blood can lead to jaundice—a yellowing of the skin and eyes—which is a clear sign of liver dysfunction.
Albumin is a protein made by the liver, and it plays an essential role in maintaining fluid balance in the bloodstream. Low levels of albumin can indicate liver disease, as the liver may be failing to produce adequate amounts of the protein.
If you experience symptoms such as chronic fatigue, jaundice (yellowing of the skin and eyes), nausea, vomiting, loss of appetite, dark urine, light-colored stools, or abdominal pain, your doctor may recommend a liver blood test. These symptoms could indicate underlying liver dysfunction that needs immediate attention.
Liver blood tests are typically conducted via a standard blood draw. A healthcare professional will collect a sample of your blood, which is then sent to a laboratory for analysis. To prepare, you may need to fast for several hours before the test, depending on the specific blood tests your doctor orders.
The findings of a liver blood test can reveal diseases, injuries, or liver function. The following are things to look for in the results of a liver blood test:
Each liver function test has a normal range of values, which may vary slightly depending on the laboratory. For instance, ALT levels typically range between 7 and 55 units per liter, while AST levels range between 10 and 40 units per liter. Your doctor will interpret your results and discuss any abnormalities with you.
Abnormal liver test results do not always signify serious liver disease. They can be caused by a variety of factors, including medications, infections, or lifestyle choices. However, persistently elevated or low levels often require further investigation, such as additional blood tests, imaging, or liver biopsies.
These are the conditions that are diagnosed with the help of liver blood test:
Hepatitis, an inflammation of the liver, can be diagnosed through elevated liver enzymes like ALT and AST. Blood tests can help differentiate between hepatitis A, B, and C, which have different causes and treatments.
Fatty liver disease occurs when excess fat builds up in the liver. Blood tests revealing high levels of ALT and AST can help identify this condition before it progresses to more severe forms, such as non-alcoholic steatohepatitis (NASH) or cirrhosis.
Cirrhosis is the advanced scarring of the liver often caused by chronic liver diseases, such as hepatitis or long-term alcohol abuse. Liver blood tests can help diagnose cirrhosis by revealing abnormal liver enzyme levels, low albumin levels, and elevated bilirubin.
Early detection of liver cancer can be aided by liver blood tests, especially those that measure AFP (alpha-fetoprotein), a protein that can be elevated in liver cancer cases.
Risk factors for liver disease include excessive alcohol consumption, obesity, chronic viral infections (such as hepatitis B and C), and a family history of liver disease. If you have any of these risk factors, your doctor may recommend regular liver function tests to monitor your liver health.
To maintain liver health, focus on a balanced diet rich in fruits, vegetables, and whole grains while limiting alcohol consumption and avoiding processed foods. Regular exercise, maintaining a healthy weight, and avoiding toxins can also help protect your liver. Additionally, staying up to date on vaccinations for hepatitis A and B can prevent liver infections.
