The Creatinine Clearance (CrCl) Calculator estimates kidney function using the Cockcroft-Gault equation to guide safe drug dosing in patients with impaired renal function.
Cockcroft-Gault Formula:
CrCl (mL/min) =
(140 − Age) × Weight (kg) ×
(Sex Factor)
72 × Serum Creatinine
Sex Factor: Male = 1, Female = 0.85
Variables:
- Age: Years.
- Weight: Actual body weight in kilograms (use ideal body weight if obese).
- Sex Factor: 0.85 for females, 1.0 for males.
- Serum Creatinine (SCr): In mg/dL (convert µmol/L → mg/dL by dividing by 88.4).
🧮 Creatinine Clearance Calculator (CrCl)
📐 Formula:
CrCl (mL/min) =
(140 − Age) × Weight (kg) ×
(Sex Factor)
72 × Serum Creatinine
Sex Factor: Male = 1, Female = 0.85
🖊️ Enter the Values:
How to Use the Calculator
Input:
- Age (years).
- Weight (kg).
- Sex (male/female).
- Serum creatinine (mg/dL or µmol/L).
Calculate:
CrCl (mL/min) =
(140 − Age) × Weight (kg) ×
(Sex Factor)
72 × Serum Creatinine
Sex Factor: Male = 1, Female = 0.85
Example Calculation
Patient Data:
- Age = 60 years
- Weight = 70 kg
- Sex = Female
- SCr = 1.0 mg/dL
Calculation:
CrCl (mL/min) =
(140 − Age) × Weight (kg) ×
(Sex Factor)
72 × Serum Creatinine
Sex Factor: Male = 1, Female = 0.85
CrCl (mL/min) =
(140 − 60) × 70 (kg) ×
0.85
72 × 1.0
CrCl (mL/min) =
80 x 70 x 0.85
72
CrCl (mL/min) =
80 x 59.5
72
CrCl (mL/min) =
4,760
72
= 66.11 mL/min
Normal Ranges
| Group | Normal CrCl |
|---|---|
| Adult Males | 95–145 mL/min |
| Adult Females | 85–125 mL/min |
| Elderly (>65) | Decline by ~1 mL/min/year |
Clinical Interpretation
| CrCl (mL/min) | Kidney Function | Drug Dosing Implications |
|---|---|---|
| >90 | Normal | Standard dosing |
| 50–89 | Mild impairment | Adjust nephrotoxic drugs (e.g., vancomycin) |
| 30–49 | Moderate impairment | Reduce doses (e.g., antibiotics, NSAIDs) |
| 15–29 | Severe impairment | Avoid nephrotoxic drugs |
| <15 | Kidney failure | Dialysis required |
Key Notes
- Weight Adjustments:
- Use ideal body weight (IBW) if obese:
- Male IBW = 50 kg + 2.3 kg per inch over 5 feet.
- Female IBW = 45.5 kg + 2.3 kg per inch over 5 feet.
- Limitations:
- Less accurate in extremes (elderly, amputees, muscle wasting).
- Not valid for acute kidney injury (AKI).
CrCl vs. eGFR
| Parameter | CrCl (Cockcroft-Gault) | eGFR (CKD-EPI) |
|---|---|---|
| Purpose | Drug dosing adjustments | CKD staging |
| Accuracy | Reflects tubular secretion | More precise for GFR <60 |
Quick Reference
| Drug | Dose Adjustment if CrCl <50 mL/min |
|---|---|
| Metformin | Contraindicated if CrCl <30 |
| Vancomycin | Increase dosing interval |
| Penicillin | Reduce dose by 25–50% |
