What laboratory tests should be obtained for a patient with known or suspected cirrhosis?

Laboratory Tests for Cirrhosis

For patients with known or suspected cirrhosis, obtain a comprehensive hepatic function panel including bilirubin (total and conjugated), AST, ALT, alkaline phosphatase, GGT, albumin, PT/INR, complete blood count with platelets, and renal function tests (creatinine, BUN, electrolytes including sodium). 1

Initial Diagnostic Laboratory Panel

The core laboratory assessment serves multiple purposes: establishing diagnosis, determining disease severity, calculating prognostic scores, and screening for complications.

Hepatic Synthetic Function Markers

• Albumin is decreased in impaired synthetic function and is a critical component of Child-Pugh scoring 1
• PT/INR values are prolonged in impaired hepatic synthetic function and are essential for both Child-Pugh and MELD scoring 1
• Bilirubin (total and conjugated) indicates advanced disease severity, with elevated conjugated bilirubin suggesting advanced disease or biliary obstruction 1

Hepatocellular Injury Markers

• AST and ALT are typically elevated in active liver injury, with AST/ALT ratio often >1 in cirrhosis 1
• Alkaline phosphatase may be elevated, particularly in cholestatic liver disease 1
• GGT is useful for detecting hepatobiliary involvement and calculating fibrosis indices 1

Hematologic Parameters

• Platelet count is specifically important as thrombocytopenia suggests portal hypertension and is a surrogate marker for advanced disease 1
• Platelet count is also essential for calculating fibrosis indices like APRI and FIB-4 1
• Complete blood count provides additional information about cytopenias related to hypersplenism 1

Renal Function

• Creatinine and BUN are essential for MELD score calculation and detecting hepatorenal syndrome 1
• Sodium is required for MELD-Na calculation, which provides improved prognostic accuracy 1

Etiologic Workup

Once cirrhosis is suspected, determine the underlying cause to guide specific management:

Viral Hepatitis Screening

• Hepatitis B panel (HBsAg, anti-HBc, anti-HBs) and hepatitis C antibody with confirmatory HCV RNA if positive 2, 1
• This testing is mandatory as antiviral therapy can prevent decompensation 2

Metabolic and Genetic Causes

• Ferritin and transferrin saturation to screen for hemochromatosis 1
• Alpha-1 antitrypsin level to screen for alpha-1 antitrypsin deficiency 1
• Ceruloplasmin for Wilson disease, particularly in younger patients 1

Autoimmune Evaluation

• Autoimmune markers (ANA, ASMA, immunoglobulins) should be considered if etiology is unclear 1

Prognostic Scoring Systems

Calculate these scores at baseline and every 6 months for ongoing risk stratification:

MELD-Na Score

• Uses bilirubin, INR, creatinine, and sodium to predict mortality 1
• Scores range from 6 to 40, with 3-month survival ranging from 90% to 7% respectively 1
• Liver transplant evaluation is indicated for MELD score ≥15 3

Child-Pugh Score

• Incorporates albumin, bilirubin, INR, ascites status, and encephalopathy grade 1
• Provides disease severity classification (Class A, B, or C) 1

Non-Invasive Fibrosis Indices

• FIB-4 index (age, AST, ALT, platelets) tracks fibrosis progression 1
• APRI score (AST/platelet ratio) provides additional fibrosis assessment 1

Ascites-Specific Testing

When ascites is present or develops, immediate diagnostic paracentesis is mandatory:

Ascitic Fluid Analysis

• Cell count with differential to diagnose spontaneous bacterial peritonitis (SBP); neutrophil count >250 cells/mm³ is diagnostic 2, 1
• Ascitic fluid total protein helps classify ascites type 1
• Serum-ascites albumin gradient (SAAG) ≥1.1 g/dL confirms portal hypertension as the cause 1
• Ascitic fluid culture by bedside inoculation into blood culture bottles 1

Additional Ascitic Fluid Tests (When Indicated)

• Cytology if malignant ascites suspected 1
• Amylase if pancreatic ascites suspected 1
• Adenosine deaminase if tuberculous peritonitis suspected 1

Monitoring Schedule for Established Cirrhosis

Compensated Cirrhosis (Every 6 Months)

• Complete metabolic panel including liver enzymes, bilirubin, albumin, creatinine, electrolytes 1, 4
• Complete blood count with platelets 1, 4
• PT/INR 1, 4
• Calculate MELD-Na, Child-Pugh, and FIB-4 scores 1, 4

Decompensated Cirrhosis (Every 1-3 Months)

• Same laboratory panel as above but with increased frequency 1
• More frequent monitoring is required due to higher risk of complications 1

Hepatocellular Carcinoma Surveillance

• Liver ultrasound every 6 months for all patients with cirrhosis 1, 4
• Alpha-fetoprotein (AFP) may be added but ultrasound alone is the standard 1

Critical Clinical Pitfalls to Avoid

Don't Rely on Normal Transaminases

• Serum aminotransferase levels may be normal in up to half of cirrhotic patients, so normal ALT/AST does not exclude cirrhosis 1
• Evaluation of disease severity should be performed regardless of ALT patterns 2

Don't Delay Diagnostic Paracentesis

• Perform diagnostic paracentesis immediately in any hospitalized patient with cirrhosis or new-onset ascites to rule out SBP 1
• Paracentesis is not contraindicated by abnormal coagulation profile; most cirrhotic patients have prolonged PT and thrombocytopenia 2

Don't Use High Thresholds for Enzyme Abnormalities

• Avoid waiting for values >1.5-2× upper limit of normal before investigating 1
• Persistent abnormalities over 3-6 months warrant further evaluation even if mildly elevated 1

Don't Routinely Check Ammonia Levels

• Routine ammonia level testing in patients with altered mental status is not recommended, as ammonia levels are variable and may be elevated in non-hepatic encephalopathy conditions 1

Endoscopic Evaluation

While not a laboratory test, upper endoscopy is part of the initial cirrhosis workup:

• Perform upper endoscopy for all patients with newly diagnosed cirrhosis unless BOTH criteria are met: platelets >150,000/μL AND liver stiffness <20 kPa by transient elastography (Baveno criteria) 1, 5
• This screens for esophageal varices requiring prophylaxis 1