What blood tests help diagnose liver cancer?

Blood Tests for Diagnosing Liver Cancer

Alpha-fetoprotein (AFP) is the primary blood test used for liver cancer diagnosis, but it should be used in conjunction with imaging studies as it has limited sensitivity and specificity when used alone. 1

Primary Blood Tests for Liver Cancer Diagnosis

• Alpha-fetoprotein (AFP): The most commonly used serum biomarker for hepatocellular carcinoma (HCC), though it has limitations:

  • Sensitivity of only 60% at a cut-off of 20 ng/mL 1
  • Specificity of 84% at a cut-off of 20 ng/mL 2
  • Higher specificity (99%) but lower sensitivity (36%) at a cut-off of 200 ng/mL 2
  • An AFP level >200 ng/mL in conjunction with imaging showing a liver mass >2 cm has high positive predictive value for HCC 1

• Standard liver function tests that should be included in the initial evaluation:

  • Bilirubin
  • Albumin
  • Alanine aminotransferase (ALT)
  • Aspartate aminotransferase (AST)
  • Alkaline phosphatase (ALP)
  • Gamma-glutamyl transferase (GGT) 1, 3

• Complete blood count (CBC) with platelet count 1

• Coagulation studies: Prothrombin time (PT)/International Normalized Ratio (INR) 1

Promising Additional Biomarkers

• Des-gamma-carboxy prothrombin (DCP), also known as protein induced by vitamin K absence-II (PIVKA-II):

  • More specific than total AFP in detecting HCC 4
  • Particularly used in Asian guidelines 1

• Lens culinaris agglutinin-reactive AFP (AFP-L3):

  • An isoform of AFP that is more specific for small HCC when >10% of total AFP 4
  • Used in conjunction with total AFP to improve diagnostic accuracy 1

• Combination of markers: Using AFP, AFP-L3, and DCP together increases sensitivity and diagnostic accuracy 4

Diagnostic Algorithm

1. Initial blood tests for suspected HCC:

   • AFP
   • Complete liver function panel (bilirubin, albumin, ALT, AST, ALP, GGT)
   • CBC with platelet count
   • PT/INR 1

2. Interpretation of AFP results:

   • AFP >200 ng/mL with a liver mass >2 cm on imaging is highly suggestive of HCC 1
   • AFP between 20-200 ng/mL requires further investigation with imaging 1
   • Normal AFP does not exclude HCC (40% of HCCs may be missed) 1, 2

3. Follow-up for elevated AFP without visible mass:

   • More frequent AFP testing and liver imaging (every 3 months) 1
   • Consider advanced imaging (triphasic CT or MRI) 1

Important Considerations and Limitations

• AFP alone is inadequate for HCC screening or diagnosis due to limited sensitivity and specificity 1

• Combination of AFP and ultrasound provides the highest sensitivity (96%) for HCC detection 2

• AST:ALT ratio >1 may indicate advanced fibrosis/cirrhosis, which is important in risk assessment for HCC 1

• Liver function tests may be abnormal in about 90% of HCC cases but are not specific for diagnosis 5

• Novel markers such as glypican-3 are being studied for improved diagnostic accuracy 4

• Blood lymphocyte counts combined with AST levels show promise for screening patients with chronic liver disease who are at risk for HCC 6

Diagnostic Confirmation

Blood tests alone are insufficient for definitive diagnosis. Confirmation typically requires:

• Imaging studies: Dynamic contrast-enhanced MRI or 4-phase multidetector CT are the most effective techniques for detecting tumors, especially those <2 cm 1

• Biopsy: May be required when imaging is inconclusive or when classic arterial enhancement is not observed 1