What blood investigations should be done in suspected liver infarction?

Blood Investigations for Suspected Liver Infarction

In suspected liver infarction, comprehensive laboratory testing should include liver function tests, coagulation profile, complete blood count, and specific tests to evaluate for vascular occlusion and underlying causes.

Core Laboratory Tests

Liver Function Tests

• Transaminases (ALT/AST): Typically markedly elevated (often >5-10× ULN) in liver infarction 1
• Alkaline phosphatase and GGT: May be elevated, especially with biliary involvement 1
• Bilirubin: Total and direct bilirubin to assess liver function 1
• Albumin and total protein: To evaluate synthetic function 1

Coagulation Profile

• Prothrombin time/INR: Essential to assess liver synthetic function 2
• Activated partial thromboplastin time (aPTT): To evaluate coagulation status 2
• Fibrinogen: May be decreased in severe liver damage 2
• D-dimer: Often elevated in vascular occlusion 2

Complete Blood Count

• Platelet count: May be decreased due to consumption or underlying liver disease 2
• Hemoglobin/hematocrit: To assess for anemia or hemoconcentration 2
• White blood cell count: May show leukocytosis in response to tissue necrosis 2

Specialized Tests for Vascular Evaluation

Thrombophilia Workup

• Factor VIII and von Willebrand factor levels: May help distinguish consumptive coagulopathy from adaptive changes in liver disease 2
• Antithrombin levels: Decreased levels may suggest consumptive coagulopathy 2

Cardiac Assessment

• Cardiac enzymes (troponin, CK-MB): To evaluate for cardiac causes of hepatic hypoperfusion 2
• ECG: To assess for arrhythmias or myocardial infarction that could lead to embolic events 2

Tests to Rule Out Alternative Diagnoses

Viral Hepatitis Panel

• Hepatitis B serology: HBsAg, anti-HBc 2
• Hepatitis C antibody: With reflex RNA testing if positive 2
• Hepatitis E testing: Particularly in acute presentations 2

Autoimmune Markers

• Antinuclear antibody (ANA): To rule out autoimmune hepatitis 2
• Anti-smooth muscle antibody (ASMA): For autoimmune hepatitis 2
• Immunoglobulin levels (IgG, IgM, IgA): May be elevated in autoimmune conditions 2

Additional Considerations

Toxicology

• Toxicology screen: To rule out drug-induced liver injury 2
• Acetaminophen level: If overdose is suspected 2
• Alcohol markers: Ethyl-glucuronide, phosphatidylethanol if alcohol hepatitis suspected 2

Metabolic Assessment

• Blood glucose: Hypoglycemia may mimic or result from severe liver injury 2
• Electrolytes and renal function: To assess for multiorgan involvement 2

Clinical Pearls and Pitfalls

• Pattern recognition is crucial: Liver infarction typically presents with a marked hepatocellular pattern of injury (R value ≥5) 2
• Traditional coagulation tests may be misleading: PT/INR and aPTT only partially evaluate hemostasis in liver disease and may overestimate bleeding risk 2
• Consider global hemostasis tests: Thromboelastography (TEG) or rotational thromboelastometry (ROTEM) may provide better assessment of coagulation status in liver disease 2
• Serial testing is important: Monitor trends in laboratory values, as rapid changes may indicate ongoing infarction or improvement 2
• Imaging correlation is essential: Laboratory findings should be interpreted in conjunction with imaging studies (ultrasound with Doppler, CT, or MRI) to confirm vascular occlusion 2, 3

When to Expedite Evaluation

• ALT/AST >5× ULN
• ALT/AST >3× ULN with total bilirubin ≥2× ULN
• Evidence of hepatic decompensation (elevated INR, encephalopathy)
• Rapid deterioration of laboratory values 1

Liver infarction is rare due to the dual blood supply (hepatic artery and portal vein), and typically occurs only when both vascular supplies are compromised 4, 3. Therefore, laboratory evaluation should focus not only on assessing liver injury but also on identifying potential vascular causes and underlying hypercoagulable states.