Thursday, June 25, 2026
🇺🇸 FDA

Clinical Tools · Hepatic Impairment · Drug Dosing

Child-Pugh Score Calculator

Calculate Child-Pugh class A, B, or C from bilirubin, albumin, INR or PT, ascites, and encephalopathy. Built for cirrhosis severity assessment, hepatic impairment studies, and drug-label dosing context.

Quick Answer

The Child-Pugh score classifies cirrhosis severity as Class A, B, or C using bilirubin, albumin, INR or PT, ascites, and hepatic encephalopathy. Pharma professionals use Child-Pugh A/B/C to define mild, moderate, and severe hepatic impairment in FDA and EMA pharmacokinetic studies, drug label dose adjustments, and clinical trial inclusion and exclusion criteria. It was developed for cirrhosis prognosis but remains the regulatory standard for hepatic impairment cohorts.

Child-Pugh score
Total Score = Bilirubin + Albumin + INR/PT + Ascites + Encephalopathy
Each variable scores 1-3 points. Class A = 5-6, Class B = 7-9, Class C = 10-15.

Calculate Child-Pugh Score

Enter bilirubin, albumin, coagulation, ascites, and encephalopathy to classify cirrhosis severity as Class A, B, or C.

Laboratory values

Use the value specified by the protocol, label, or source document.

Clinical findings

Child-Pugh class

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-

Total score
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points
Bilirubin
-
points
Albumin
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points
INR/PT
-
points
Ascites
-
points
Encephalopathy
-
points

How to Use the Child-Pugh Calculator

1
Enter total bilirubin and serum albumin from the same clinical assessment window when possible.
2
Choose either INR or prothrombin time prolongation. Use the value specified by the protocol, label, or source document.
3
Select ascites severity and hepatic encephalopathy grade based on clinical assessment.
4
Review the total score, Child-Pugh class, and hepatic impairment category used in many drug labels and PK study designs.

Worked Example

Example calculation

Inputs: bilirubin 2.4 mg/dL, albumin 3.1 g/dL, INR 1.9, mild ascites, no encephalopathy.

Component scores: bilirubin 2 + albumin 2 + INR 2 + ascites 2 + encephalopathy 1 = 9 points.

Interpretation: 9 points = Child-Pugh Class B, often mapped to moderate hepatic impairment in pharmacokinetic studies and drug labeling.

Child-Pugh Classes and Hepatic Impairment

Class A 5-6 points

Well-compensated cirrhosis; commonly mapped to mild hepatic impairment.

Class B 7-9 points

Significant functional compromise; commonly mapped to moderate hepatic impairment.

Class C 10-15 points

Decompensated or severe liver dysfunction; commonly mapped to severe hepatic impairment.

Pharma & clinical trial context

Child-Pugh classification is the standard stratification for hepatic impairment pharmacokinetic studies and FDA/EMA drug labeling. Sponsors enroll Child-Pugh A, B, and sometimes C cohorts to characterize exposure (AUC, Cmax), clearance changes, and safety margins, then draft label language for dose reduction, use with caution, or contraindication in specific classes.

Hepatic impairment PK studies are especially relevant when hepatic metabolism or biliary excretion accounts for a substantial portion of elimination, when metabolism is unknown, or when the drug has a narrow therapeutic range. Trial protocols often exclude Child-Pugh B or C patients when prior PK data show elevated exposure or when safety margins are narrow—while renal function is assessed separately using eGFR or CrCl via our GFR Calculator and Creatinine Clearance Calculator.

Child-Pugh addresses cirrhosis severity; FIB-4 screens for advanced fibrosis before decompensation. Use our FIB-4 Index Calculator for fibrosis risk and this tool for hepatic impairment dosing context. For PK interpretation, pair Child-Pugh class with our Half-Life Calculator and Dosage Calculator when evaluating exposure changes and dose adjustments.

Drug Dosing Caveats

Child-Pugh is practical and common, but it was originally developed for cirrhosis prognosis rather than direct measurement of hepatic metabolic capacity. Two patients in the same Child-Pugh class can have different CYP activity, transporter function, albumin binding, portal-systemic shunting, cholestasis, renal function, and infection status.

Use Child-Pugh class as a label interpretation aid, not as a standalone dose calculator. Always check the specific product label, hepatic impairment study data, contraindications, exposure-response relationship, and patient-specific clinical factors.

Scoring Reference

Criterion 1 point 2 points 3 points
Bilirubin <2 mg/dL 2-3 mg/dL >3 mg/dL
Albumin >3.5 g/dL 2.8-3.5 g/dL <2.8 g/dL
INR / PT <1.7 / <4 sec 1.7-2.3 / 4-6 sec >2.3 / >6 sec
Ascites None Mild or controlled Moderate-severe or refractory
Encephalopathy None Grade I-II Grade III-IV

Evidence & sources

Frequently Asked Questions

The Child-Pugh (Child-Turcotte-Pugh) score estimates cirrhosis severity using five variables: total bilirubin, serum albumin, INR or prothrombin time prolongation, ascites, and hepatic encephalopathy. Each variable scores 1 to 3 points, yielding a total from 5 to 15. It was originally developed to predict surgical mortality in cirrhosis but is now widely used to classify hepatic impairment in drug development and labeling.
Class A is 5–6 points and represents well-compensated cirrhosis, commonly mapped to mild hepatic impairment. Class B is 7–9 points and reflects significant functional compromise, mapped to moderate hepatic impairment. Class C is 10–15 points and indicates decompensated or severe hepatic impairment. FDA and EMA hepatic impairment PK studies typically enroll separate cohorts for each class.
Prescribing information often references Child-Pugh A, B, or C when describing hepatic impairment dose adjustments. Labels may recommend no change in Class A, dose reduction or monitoring in Class B, and contraindication or avoidance in Class C for hepatically cleared drugs. Always apply the specific product label, exposure-response data, and patient factors—not a generic class interpretation alone.
No. Child-Pugh correlates imperfectly with CYP enzyme activity, transporter function, and biliary excretion. Two patients in the same class can have different metabolic capacity, albumin binding, portal-systemic shunting, and renal function. It is a regulatory stratification tool, not a direct clearance predictor. PK studies measure actual exposure changes within Child-Pugh cohorts.
FDA guidance recommends hepatic impairment PK evaluation when hepatic metabolism or biliary excretion accounts for a substantial portion of elimination, when metabolism is unknown, or when the drug has a narrow therapeutic range. Sponsors typically enroll Child-Pugh A, B, and sometimes C subjects to characterize exposure changes and inform label recommendations for dose adjustment or contraindication.
MELD (Model for End-Stage Liver Disease) uses bilirubin, INR, creatinine, and optionally sodium to prioritize liver transplant allocation. Child-Pugh adds albumin, ascites, and encephalopathy and remains the standard for hepatic impairment drug studies and labeling. MELD better predicts short-term transplant mortality; Child-Pugh better maps to mild/moderate/severe impairment categories in PK protocols.
FIB-4 estimates advanced fibrosis risk before decompensation using age, AST, ALT, and platelets. Child-Pugh classifies established cirrhosis severity including decompensation markers. A patient may have elevated FIB-4 with compensated cirrhosis (Child-Pugh A) or progress to Child-Pugh B/C as ascites or encephalopathy develop. For fibrosis screening, use our FIB-4 Index Calculator; for hepatic impairment dosing, use Child-Pugh.
Ascites scores 1 point if absent, 2 if mild or controlled with diuretics, and 3 if moderate-severe or refractory. Hepatic encephalopathy scores 1 if absent, 2 for grade I–II or precipitant-induced episodes, and 3 for grade III–IV or chronic encephalopathy. These clinical components distinguish compensated from decompensated cirrhosis and often drive the difference between Class A and Class B/C.
FDA guidance on pharmacokinetics in patients with impaired hepatic function defines mild, moderate, and severe hepatic impairment using Child-Pugh Class A, B, and C. Sponsors use these categories to design PK studies, report exposure changes, and draft label language for dose adjustment, use with caution, or contraindication. The guidance also discusses when dedicated hepatic impairment studies may be waived.
Protocols frequently exclude Child-Pugh B or C patients when hepatic metabolism is significant, when prior hepatic impairment PK data show elevated exposure, or when safety margins are narrow. Some oncology or palliative trials allow Child-Pugh A only. Hepatic impairment cohort studies may require Child-Pugh A and B enrollment while excluding Class C due to safety. Always apply protocol-specific definitions, not calculator output alone.
Avoid relying on Child-Pugh alone during acute liver failure, acute-on-chronic liver failure, active variceal bleeding, recent large-volume paracentesis without albumin, or when laboratory values are rapidly changing. It is not validated for non-cirrhotic liver disease, isolated cholestasis without cirrhosis, or pediatric populations. Do not use it as a transplant priority score—that role belongs to MELD or PELD.
In the original validation cohorts, Child-Pugh Class A had approximately 1-year survival around 100%, Class B around 80%, and Class C around 45%. These prognostic estimates reflect pre-transplant-era surgical risk and decompensation severity. Modern management has improved outcomes, but higher classes still indicate greater mortality risk and poorer reserve—relevant context when interpreting hepatic impairment study safety and label contraindications.

Related Tools

FIB4 FIB-4 Index Calculator GFR GFR Calculator CrCl Creatinine Clearance t1/2 Half-Life Calculator Dose Dosage Calculator

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