MedCalc

MedCalc is a JavaScript library providing medical calculators for nephrology and kidney function assessment. It implements evidence-based formulas commonly used in clinical practice for evaluating kidney disease and acute kidney injury.

Features

✓ CKD-EPI 2021 Equation - Calculate estimated Glomerular Filtration Rate (eGFR)
✓ GFR Staging - Determine chronic kidney disease stages based on eGFR
✓ KDIGO Classification - Assess acute kidney injury severity
✓ Zero Dependencies - Lightweight and fast
✓ Type Safe - Built with modern JavaScript and proper validation
✓ Well Tested - Comprehensive test suite with clinical reference values

Installation

npm install medcalc

Usage

CKD-EPI Equation (2021)

Calculate estimated Glomerular Filtration Rate using the latest CKD-EPI creatinine equation:

import { ckdEpi } from 'medcalc'

// Calculate eGFR for a 60-year-old male with creatinine 1.4 mg/dL
const eGFR = ckdEpi({
  creat: 1.4, // Serum creatinine in mg/dL
  age: 60, // Age in years
  gender: 'M', // 'M' for male, 'F' for female
})

console.log(eGFR) // 57.5 mL/min/1.73 m²

GFR Staging

Determine chronic kidney disease stage based on eGFR:

import { gfrStage } from 'medcalc'

const stage = gfrStage({ tfg: 45 }) // tfg = eGFR value
console.log(stage) // '3b'

// Stage reference:
// '1': ≥90 mL/min/1.73 m²
// '2': 60-89 mL/min/1.73 m²
// '3a': 45-59 mL/min/1.73 m²
// '3b': 30-44 mL/min/1.73 m²
// '4': 15-29 mL/min/1.73 m²
// '5': <15 mL/min/1.73 m²

KDIGO Acute Kidney Injury Classification

Assess acute kidney injury severity using KDIGO criteria:

import { kdigo } from 'medcalc'

// Based on creatinine change
const akiStage = kdigo({
  baseCreat: 1.0, // Baseline creatinine (mg/dL)
  currentCreat: 2.1, // Current creatinine (mg/dL)
})

console.log(akiStage) // 2 (Stage 2 AKI)

// Based on urine output
const akiStageUrine = kdigo({
  diuresis: 200, // Urine output (mL)
  interval: 8, // Time interval (hours)
  weight: 70, // Patient weight (kg)
})

// For patients on dialysis
const akiStageDialysis = kdigo({
  inDialysis: true,
})

console.log(akiStageDialysis) // 3 (Stage 3 AKI)

API Reference

ckdEpi(params)

Calculates estimated GFR using the CKD-EPI 2021 equation.

Parameters:

• creat (number): Serum creatinine in mg/dL
• age (number): Age in years
• gender (string): 'M' for male, 'F' for female

Returns: number | undefined - eGFR in mL/min/1.73 m², or undefined for invalid input

gfrStage(params)

Determines CKD stage based on eGFR value.

Parameters:

• tfg (number): eGFR value in mL/min/1.73 m²

Returns: string | undefined - Stage ('1', '2', '3a', '3b', '4', '5'), or undefined for invalid input

kdigo(params)

Classifies acute kidney injury using KDIGO criteria.

Parameters:

• baseCreat (number, optional): Baseline creatinine in mg/dL
• currentCreat (number, optional): Current creatinine in mg/dL
• diuresis (number, optional): Urine output in mL
• interval (number, optional): Time interval in hours
• weight (number, optional): Patient weight in kg
• inDialysis (boolean, optional): Whether patient is on dialysis

Returns: number | undefined - AKI stage (1, 2, or 3), or undefined if no AKI

Clinical References

• CKD-EPI 2021: Kidney Disease: Improving Global Outcomes (KDIGO)
• KDIGO AKI Guidelines: Clinical Practice Guideline for Acute Kidney Injury
• Test reference values from: Brazilian Society of Nephrology Calculator

Development

# Install dependencies
npm install

# Run tests
npm test

# Run tests in watch mode
npm run test:watch

# Lint code
npm run lint

License

Copyright © 2018 Luiz Américo Pereira Câmara. This source code is licensed under the MIT license found in the LICENSE.txt file. The documentation to the project is licensed under the CC BY-SA 4.0 license.

Made with ♥ by Luiz Américo Pereira Câmara and contributors