fibrosis_4_calculator.py•7.25 kB
"""
Fibrosis-4 (FIB-4) Index Calculator
"""
import math
from typing import Dict, Any
from medcalc import (
BaseCalculator,
CalculatorInfo,
Parameter,
ParameterType,
ValidationResult,
CalculationResult,
register_calculator
)
from medcalc.utils import round_number
@register_calculator("fibrosis_4")
class Fibrosis4Calculator(BaseCalculator):
"""纤维化-4 (FIB-4) 指数计算器实现"""
def get_info(self) -> CalculatorInfo:
return CalculatorInfo(
id=19,
name="Fibrosis-4 (FIB-4) Index",
category="hepatology",
description="Calculate FIB-4 index to assess liver fibrosis using age, AST, ALT, and platelet count",
parameters=[
Parameter(
name="age",
type=ParameterType.NUMERIC,
required=True,
unit="years",
min_value=18,
max_value=120,
description="Patient age in years"
),
Parameter(
name="ast",
type=ParameterType.NUMERIC,
required=True,
unit="U/L",
min_value=5,
max_value=1000,
description="Aspartate aminotransferase (AST) level in U/L"
),
Parameter(
name="alt",
type=ParameterType.NUMERIC,
required=True,
unit="U/L",
min_value=5,
max_value=1000,
description="Alanine aminotransferase (ALT) level in U/L"
),
Parameter(
name="platelet_count",
type=ParameterType.NUMERIC,
required=True,
unit="×10⁹/L",
min_value=10,
max_value=1000,
description="Platelet count in ×10⁹/L"
)
]
)
def validate_parameters(self, parameters: Dict[str, Any]) -> ValidationResult:
"""验证参数"""
errors = []
# 获取参数值并转换为浮点数
try:
age = float(parameters.get("age", 0)) if parameters.get("age") is not None else None
except (ValueError, TypeError):
errors.append("Age must be a valid number")
age = None
try:
ast = float(parameters.get("ast", 0)) if parameters.get("ast") is not None else None
except (ValueError, TypeError):
errors.append("AST level must be a valid number")
ast = None
try:
alt = float(parameters.get("alt", 0)) if parameters.get("alt") is not None else None
except (ValueError, TypeError):
errors.append("ALT level must be a valid number")
alt = None
try:
platelet_count = float(parameters.get("platelet_count", 0)) if parameters.get("platelet_count") is not None else None
except (ValueError, TypeError):
errors.append("Platelet count must be a valid number")
platelet_count = None
# 检查必需参数
if age is None:
errors.append("Missing required parameter: age")
if ast is None:
errors.append("Missing required parameter: ast")
if alt is None:
errors.append("Missing required parameter: alt")
if platelet_count is None:
errors.append("Missing required parameter: platelet_count")
# 验证数值范围
if age is not None:
if age < 18 or age > 120:
errors.append("Age must be between 18 and 120 years")
if ast is not None:
if ast < 5 or ast > 1000:
errors.append("AST level must be between 5 and 1000 U/L")
if alt is not None:
if alt < 5 or alt > 1000:
errors.append("ALT level must be between 5 and 1000 U/L")
if platelet_count is not None:
if platelet_count < 10 or platelet_count > 1000:
errors.append("Platelet count must be between 10 and 1000 ×10⁹/L")
return ValidationResult(
is_valid=len(errors) == 0,
errors=errors
)
def calculate(self, parameters: Dict[str, Any]) -> CalculationResult:
"""执行计算"""
# 获取参数值并转换为浮点数
age = float(parameters.get("age"))
ast = float(parameters.get("ast"))
alt = float(parameters.get("alt"))
platelet_count = float(parameters.get("platelet_count"))
# 计算 FIB-4: (年龄 × AST) / (血小板计数(十亿/L) × √ALT)
# 血小板计数已经是 ×10⁹/L 单位，所以直接使用
fib4_score = round_number((age * ast) / (platelet_count * math.sqrt(alt)))
# 生成解释和风险评估
explanation = self._generate_explanation(age, ast, alt, platelet_count, fib4_score)
risk_assessment = self._get_risk_assessment(fib4_score)
return CalculationResult(
value=fib4_score,
unit="",
explanation=explanation,
metadata={
"age": age,
"ast": ast,
"alt": alt,
"platelet_count": platelet_count,
"formula": "FIB-4 = (Age × AST) / (Platelet count (×10⁹/L) × √ALT)",
"risk_assessment": risk_assessment
}
)
def _generate_explanation(self, age: float, ast: float, alt: float, platelet_count: float, fib4_score: float) -> str:
"""生成计算解释"""
explanation = "The formula for computing Fibrosis-4 is FIB-4 = (Age × AST) / (Platelet count (in ×10⁹/L) × √ALT), "
explanation += "where platelet count is in billions per L, and the units for AST and ALT are both U/L.\n"
explanation += f"The patient's age is {age} years.\n"
explanation += f"The patient's concentration of AST is {ast} U/L.\n"
explanation += f"The patient's concentration of ALT is {alt} U/L.\n"
explanation += f"The patient's platelet count is {platelet_count} ×10⁹/L.\n"
sqrt_alt = round_number(math.sqrt(alt))
explanation += f"Plugging these values into the formula, we get ({age} × {ast}) / ({platelet_count} × √{alt}) = "
explanation += f"({age} × {ast}) / ({platelet_count} × {sqrt_alt}) = {fib4_score}.\n"
explanation += f"Hence, the Fibrosis-4 score is {fib4_score}."
return explanation
def _get_risk_assessment(self, fib4_score: float) -> str:
"""获取风险评估"""
if fib4_score < 1.45:
return "Low risk of advanced fibrosis (F3-F4)"
elif fib4_score <= 3.25:
return "Intermediate risk of advanced fibrosis - further evaluation recommended"
else:
return "High risk of advanced fibrosis (F3-F4)"