What Is the Glomerular Filtration Rate (Cockcroft-Gault) Calculator?
Creatinine clearance measures the volume of blood plasma cleared of endogenous creatinine per unit time.
It serves as a primary surrogate marker for glomerular filtration rate in pharmacokinetics.
How Does the Glomerular Filtration Rate (Cockcroft-Gault) Calculator Work?
Estimates daily creatinine production from age and total body mass.
Divides by steady-state serum creatinine concentration to calculate renal clearance in mL/min.
Applies 0.85 correction factor for females.
Glomerular Filtration Rate (Cockcroft-Gault) Calculator Formula & Variables
The core mathematical equation utilized by this calculator is expressed as:
Cockcroft-Gault formula relating muscle creatinine generation and renal tubular elimination.
How to Use the Glomerular Filtration Rate (Cockcroft-Gault) Calculator
- Enter patient age in years and weight in kg.
- Enter measured serum creatinine in mg/dL.
- Select biological sex (Male or Female).
Step-by-Step Example Calculation
Geriatric Renal Function Check
Input Values:
Understanding Your Result
Normal CrCl is 90 to 130 mL/min.
Values below 60 mL/min indicate moderate renal impairment requiring dose reductions for narrow therapeutic index drugs.
Factors That Affect the Result
- Muscle mass: Amputees, paraplegics, or malnourished patients produce less creatinine, leading to overestimation of kidney function.
- Obesity: In severely obese patients, ideal or adjusted body weight is often substituted.
When Should You Use This Calculator?
- Calculating renal dosage adjustments for antibiotics, chemotherapeutics, and anticoagulants.
- FDA clinical trial drug labeling compliance.
Assumptions & Limitations
- Requires stable renal function; invalid in acute kidney injury (AKI) where serum creatinine is rapidly changing.
- Not normalized to 1.73 m² body surface area (unlike CKD-EPI).
Frequently Asked Questions
Calculation Accuracy & Reference Note
Standard clinical equation validated in FDA pharmacokinetics guidances.