Laboratory-Based Scoring of Cirrhosis Severity
The Child-Pugh score is the primary laboratory-based tool for scoring cirrhosis severity, incorporating five parameters: total bilirubin, serum albumin, prothrombin time/INR, plus clinical assessments of ascites and hepatic encephalopathy, with scores ranging from 5-15 points that classify patients into prognostic classes A (5-6 points), B (7-9 points), or C (10-15 points). 1, 2
Child-Pugh Score Components and Calculation
The Child-Pugh score uses three objective laboratory values and two clinical parameters, each scored 1-3 points 3, 1:
Laboratory Parameters:
- Total bilirubin: <2 mg/dL = 1 point; 2-3 mg/dL = 2 points; >3 mg/dL = 3 points 3, 1
- Serum albumin: >3.5 g/dL = 1 point; 2.8-3.5 g/dL = 2 points; <2.8 g/dL = 3 points 3, 1
- Prothrombin time/INR: <1.7 or PT <4 seconds prolonged = 1 point; INR 1.7-2.3 or PT 4-6 seconds = 2 points; INR >2.3 or PT >6 seconds = 3 points 3, 1
Clinical Parameters:
- Hepatic encephalopathy: None = 1 point; Grade 1-2 = 2 points; Grade 3-4 = 3 points 3, 1
- Ascites: Absent = 1 point; Slight = 2 points; Moderate to severe = 3 points 3, 1
Prognostic Classification
Child-Pugh Class A (5-6 points) indicates 90% 5-year survival, Class B (7-9 points) indicates 80% 5-year survival, and Class C (10-15 points) indicates >33% 1-year mortality. 1, 2
The classification directly guides treatment intensity and eligibility for interventions 3, 2:
- Class A patients can undergo elective surgery and receive most anticoagulants safely 3, 2
- Class B patients require cautious medication dosing and careful perioperative assessment 3, 2
- Class C patients should receive only supportive care, avoid elective surgery, and be evaluated urgently for liver transplantation 2
Complementary Scoring Systems
MELD Score (Model for End-Stage Liver Disease)
The MELD score provides superior short-term mortality prediction using only three objective laboratory values: serum bilirubin, serum creatinine, and INR. 1, 2, 4
The MELD score is calculated as: 3.78×ln[bilirubin mg/dL] + 11.2×ln[INR] + 9.57×ln[creatinine mg/dL] + 6.43 5, 6
MELD score ≥15 is an indication for liver transplantation evaluation. 7, 5
The critical advantage of MELD over Child-Pugh is inclusion of renal function (creatinine), which is an independent mortality predictor not captured by Child-Pugh scoring 2, 4. MELD is the standard for transplant organ allocation in the United States 4, 6.
ALBI Score (Albumin-Bilirubin)
The ALBI score uses only albumin and bilirubin levels, eliminating subjective variables like ascites and encephalopathy 1, 2, 4. This score is particularly useful for predicting post-hepatectomy liver failure and outcomes in stable decompensated cirrhosis 2, 4.
Clinical Application Algorithm
For initial assessment of any cirrhotic patient, obtain these laboratory tests: 1, 2, 4
- Total bilirubin
- Serum albumin
- Prothrombin time/INR
- Serum creatinine (for MELD calculation)
Calculate both Child-Pugh and MELD scores at diagnosis and every 6 months during follow-up. 7, 5
Use Child-Pugh classification to guide treatment decisions (medication dosing, procedural eligibility, bleeding risk stratification) 3, 2
Use MELD score for transplant evaluation and short-term mortality prediction 2, 4, 7
Critical Pitfalls and Limitations
The Child-Pugh score contains subjective components (ascites and encephalopathy grading) that introduce inter-observer variability. 1, 4
The most significant limitation of Child-Pugh is the absence of renal function assessment, which is a critical prognostic factor. 1, 2 Serum creatinine should always be evaluated alongside Child-Pugh scoring, as renal dysfunction, hyponatremia, and reduced glomerular filtration rate are independent mortality predictors 2.
A 2-point worsening of the Child-Pugh score or progression from Class A to B accurately indicates worsening health status and increased mortality risk. 1
Development of complications such as ascites, variceal bleeding, or hepatorenal syndrome dramatically impacts prognosis, with 5-year survival dropping to 20-50%. 1 The median survival after onset of ascites is only 1.1 years, and after hepatic encephalopathy is 0.92 years 5.
Severe hyponatremia (≤125 mmol/L) is a better mortality predictor than MELD-Na in patients with refractory ascites and should trigger immediate transplant evaluation regardless of Child-Pugh class. 2
Enhanced Prognostic Assessment
Recent evidence suggests that incorporating serum creatinine as a sixth variable in the Child-Pugh score (creating a "modified Child-Pugh score" ranging from 5-19 points) significantly enhances prognostic accuracy, particularly in patients with moderate to severe hepatic encephalopathy 8. This modification showed an area under the curve of 0.852 for predicting complications and survival 8.