Which laboratory tests should be ordered to evaluate an adult patient with suspected cirrhosis?

Laboratory Evaluation for Suspected Cirrhosis

For adults with suspected cirrhosis, order a comprehensive metabolic panel, complete blood count with platelets, PT/INR, albumin, liver enzymes (AST, ALT, GGT, alkaline phosphatase), bilirubin, and abdominal ultrasound as the core initial workup. 1, 2, 3

Core Laboratory Panel

The essential blood tests for evaluating suspected cirrhosis include:

• Complete blood count with platelet count - Thrombocytopenia (platelet count <160 × 10³/μL) strongly suggests portal hypertension and likely cirrhosis (LR 6.3), while platelets ≥160 × 10³/μL lower the likelihood (LR 0.29) 1, 3, 4

• Comprehensive metabolic panel - Must include AST, ALT, alkaline phosphatase, total and conjugated bilirubin, albumin, and creatinine to assess synthetic function and disease severity 1, 2, 3

• PT/INR - Critical for assessing hepatic synthetic function and calculating prognostic scores (Child-Pugh and MELD) 3, 5

• GGT - Elevated in approximately 75% of habitual drinkers and useful for detecting hepatobiliary involvement 2, 3

Pattern Recognition in Laboratory Results

Key laboratory patterns that increase the likelihood of cirrhosis:

• AST/ALT ratio >2 is highly suggestive of alcoholic liver disease, with ratios >3 being particularly specific 2, 3
• AST and ALT rarely exceed 300-400 IU/L in pure alcoholic cirrhosis; higher values suggest alternative etiologies like drug-induced injury or ischemic hepatitis 2, 3
• Hypoalbuminemia indicates decreased synthetic function and advanced disease 3
• Elevated INR or prolonged PT indicates impaired hepatic synthetic capacity 3

Extended Etiologic Workup

After the core panel, perform a standard liver aetiology screen including:

• Hepatitis B surface antigen (HBsAg) 1
• Hepatitis C antibody with reflex PCR if positive 1, 2
• Autoimmune markers: anti-mitochondrial antibody, anti-smooth muscle antibody, antinuclear antibody, serum immunoglobulins 1
• Iron studies: simultaneous serum ferritin and transferrin saturation (>45% suggests hemochromatosis) 1
• Abdominal ultrasound to assess liver morphology, identify fatty liver, and evaluate for signs of portal hypertension 1

Non-Invasive Fibrosis Assessment

For patients with NAFLD or alcoholic liver disease, calculate FIB-4 score as the first-line non-invasive assessment to identify advanced fibrosis:

• FIB-4 <1.3 (age <65 years) or <2.0 (age ≥65 years) indicates low risk and can be managed in primary care 1, 3
• FIB-4 1.3-3.25 indicates indeterminate risk and warrants further evaluation with elastography or specialist referral 1
• FIB-4 >3.25 suggests advanced fibrosis/cirrhosis and requires specialist referral 1

Vibration-controlled transient elastography (VCTE/Fibroscan) provides additional diagnostic accuracy:

• Liver stiffness ≥11.0 kPa in hepatitis B patients suggests cirrhosis (sensitivity 81%, specificity 83%) 1
• Liver stiffness >16 kPa in alcoholic liver disease warrants referral to secondary care for advanced disease 1, 3
• For NAFLD, elastography has good performance (sensitivity 90%, specificity 87%) but current evidence has methodological limitations 1

Prognostic Scoring Systems

Calculate these scores using the laboratory results obtained:

• MELD-Na score (uses bilirubin, INR, creatinine, sodium) predicts mortality; scores ≥15 warrant transplant evaluation 3, 5
• Child-Pugh score (uses albumin, bilirubin, INR plus clinical parameters) assesses cirrhosis severity 3, 5
• Bonacini cirrhosis discriminant score >7 increases likelihood of cirrhosis (LR 9.4) 4
• Lok index <0.2 (derived from platelets, AST, ALT, INR) effectively excludes cirrhosis (LR 0.09) 4

Screening for Complications

Once cirrhosis is confirmed or highly suspected:

• Diagnostic paracentesis should be performed immediately in all patients with new-onset ascites to rule out spontaneous bacterial peritonitis and calculate serum-ascites albumin gradient (SAAG) 3
• Hepatocellular carcinoma surveillance with ultrasound every 6 months is essential, as incidence ranges from 7-16% at 5 years 1, 3
• Esophageal varices screening should be arranged through gastroenterology 5

Critical Pitfalls to Avoid

• Normal liver enzymes do not exclude cirrhosis - up to 40% of patients with cirrhosis are asymptomatic and may have minimal laboratory abnormalities 1, 6, 7
• Isolated elevated ferritin is commonly seen in dysmetabolic iron overload syndrome (alcohol excess, NAFLD) and does not reflect hemochromatosis unless transferrin saturation is also >45% 1
• AST >500 IU/L or ALT >200 IU/L are uncommon in pure alcoholic hepatitis and should prompt evaluation for alternative etiologies such as acetaminophen toxicity or viral hepatitis 2
• Liver biopsy remains the gold standard but should only be pursued when non-invasive evaluation is indeterminate, etiology remains unknown, or results would alter management 5, 7

Monitoring Schedule

• Decompensated cirrhosis: liver function tests every 1-3 months 3
• Stable compensated cirrhosis: laboratory monitoring every 6 months including Child-Pugh and MELD score components 3, 5