Extraction Ratio Calculation

Introduction to Extraction Ratio Calculation

The extraction ratio (ER) is a pharmacokinetic parameter used to describe the efficiency of drug removal from the blood by an eliminating organ, such as the liver or kidney. In this formula, ER represents the extraction ratio, Cv is the concentration of the drug in venous blood, and Ca is the concentration of the drug in arterial blood. The result of this calculation provides insight into the extent of drug extraction and the efficiency of the elimination process. Extraction ratios can range from 0 to 1, where a value close to 1 indicates high extraction (efficient removal), and a value closer to 0 indicates minimal extraction.

Parameter usage:

• Cv = concentration of drug in venous blood
• Ca = concentration of drug in arterial blood

Output:

• ER = extraction ratio

Data validation

The concentration values should be positive and Cv should be greater than Ca.

Summary

This calculator evaluates the efficiency of drug removal from the blood, offering valuable information for pharmacokinetic analysis and drug dosing recommendations.