Blood Tests: Detecting Disorders Through Liver Function Tests

Liver function tests (LFTs) are blood tests that assess liver health by measuring levels of proteins, liver enzymes, and bilirubin. These tests are commonly ordered during routine health screenings or to investigate symptoms of liver disease, such as jaundice or abdominal pain. LFTs help diagnose and monitor the severity of liver conditions and evaluate the effectiveness of treatments.

Key Indicators in Liver Function Tests

Liver function tests include several key indicators that help assess liver health:

  • Alanine Aminotransferase (ALT): This enzyme, found primarily in the liver, is released into the bloodstream when liver cells are damaged. Elevated levels of ALT can indicate liver injury.
  • Aspartate Aminotransferase (AST): Similar to ALT, AST is an enzyme found in the liver and other organs. High levels suggest liver damage but may also indicate problems in other organs.
  • Alkaline Phosphatase (ALP): An enzyme associated with the bile ducts; high ALP levels can indicate bile duct problems or bone disease.
  • Bilirubin: This substance is produced during the normal breakdown of red blood cells, processed by the liver. High bilirubin levels can lead to jaundice, indicating potential liver dysfunction.
  • Albumin and Total Protein: These tests measure the liver’s ability to synthesize proteins. Low levels of albumin or total protein can suggest liver disease.

Common Liver Disorders Revealed by Tests

Liver function tests can help diagnose a variety of liver disorders, some of which include:

Hepatitis

Viral infections like hepatitis A, B, and C can cause inflammation of the liver, often reflected by elevated ALT and AST levels.

Cirrhosis

This is a late stage of scarring (fibrosis) of the liver caused by many forms of liver diseases and conditions, such as hepatitis and chronic alcoholism. LFTs typically show decreased albumin levels and altered prothrombin time in cirrhosis.

Fatty Liver Disease

Characterised by an excess buildup of fat in the liver, this condition is indicated by increased ALT and AST levels. It can occur as nonalcoholic fatty liver disease (NAFLD) or alcoholic liver disease (ALD).

Bile Duct Obstruction

This can lead to elevated levels of ALP and bilirubin, as bile cannot flow properly from the liver to the intestines.

Liver Cancer

Primary liver cancer or metastatic cancer of the liver may be indicated by significant changes in liver enzyme levels, but further diagnostic tests are required to confirm the presence of cancer.

The Importance of Regular Liver Function Testing

Regular liver function testing is necessary for early detection and management of liver disorders, potentially preventing severe complications. These tests allow for monitoring the progression of existing liver conditions and assessing the effectiveness of treatment strategies.

For people at higher risk due to factors such as alcohol consumption, viral hepatitis, or a family history of liver disease, routine testing is recommended. Regular LFTs help maintain liver health and ensure timely intervention when needed.

What Your Liver Function Test Means

Understanding your liver function test results involves recognising what different measurements indicate about liver health:

  • Elevated ALT and AST: These enzyme levels typically rise when liver cells are damaged, as seen in hepatitis or cirrhosis.
  • Low ALT and AST: Lower than normal levels may occur in severe liver damage where the liver has lost its ability to function properly.
  • High Bilirubin: Elevated bilirubin levels suggest liver processing or bile flow issues, often presenting as jaundice.

Conclusion

Liver function tests are indispensable tools for diagnosing and managing liver diseases. By providing insights into liver health, these tests enable timely interventions and informed treatment decisions.