What is lft test

What is a Liver Function Test?

A Liver Function Test (LFT) is a blood test panel that measures various enzymes, proteins, and other substances produced by or processed through the liver. Healthcare providers use LFTs to assess how well the liver is functioning, screen for liver disease, monitor chronic conditions, and evaluate the effects of medications. The test involves drawing a blood sample and analyzing it in a laboratory for specific markers.

Components of LFT

A typical LFT panel includes several key measurements. ALT (Alanine Aminotransferase) and AST (Aspartate Aminotransferase) are liver enzymes that increase when the liver is damaged or inflamed. ALP (Alkaline Phosphatase) helps identify bile duct problems or bone disease. Bilirubin levels indicate whether the liver is properly processing and excreting waste. Albumin measures a protein essential for nutrient transport, and GGT (Gamma-Glutamyl Transferase) is another enzyme suggesting liver or bile duct dysfunction.

Why LFTs are Ordered

Doctors order LFTs for various reasons including diagnosing suspected liver disease, monitoring patients with known liver conditions such as hepatitis or cirrhosis, evaluating abdominal pain and jaundice symptoms, assessing medication side effects on the liver, and screening before starting medications known to affect liver function. Regular monitoring with LFTs helps detect liver problems early when treatment is most effective.

Interpreting LFT Results

Normal LFT values vary by laboratory but generally indicate proper liver function. Elevated ALT or AST suggests liver cell damage from conditions like hepatitis, fatty liver disease, or cirrhosis. Elevated ALP may indicate cholestasis or bile duct obstruction. High bilirubin causes jaundice and suggests impaired liver function or hemolysis. Low albumin indicates chronic liver disease or malnutrition. Healthcare providers interpret these results in clinical context with other findings.

Limitations and Follow-up

LFTs are screening and monitoring tools but don't diagnose specific conditions alone. Abnormal results require further investigation with imaging tests, additional blood work, or liver biopsy. Some medications, alcohol consumption, and recent exercise can temporarily affect LFT values. Physicians consider timing, patient symptoms, and medical history when interpreting results and determining whether follow-up testing is necessary.