Calculate creatinine clearance and assess kidney function.
Cockcroft–Gault estimate = [(140 − Age) × Weight] ÷ (72 × Serum creatinine), with the applicable sex adjustment.The estimate uses the measurement, age and other fields requested by the selected equation. Laboratory methods, units, timing, medication, medical history and population-specific limitations can materially affect interpretation.
The Creatinine Clearance Calculator allows you to calculate an estimated creatinine clearance (usually expressed in mL/min) based upon the Cockcroft-Gault equation. This equation typically requires input of your age, sex, body weight and the measured value of your serum (blood) creatinine concentration. Creatinine clearance is a non-diagnostic indicator of renal function utilized in some situations for medical management such as adjusting medication dosage.
This number does not mean and must not be taken in isolation from lab values a thorough history weight and your doctors overall assessment of your ability to maintain your body.
Enter the measurements exactly as reported or measured and make sure the units match the calculator fields.
Care of the inputWeight may need to be carefully considered. While Cockroft-Gault traditionally includes a weight variable, providers have reported using actual weight, ideal body weight or some other defined weight in patients for a number of different uses. Adhere to thecalculator's specified input, or the instructions provided by the user for defining the patient's weight.
Estimating Clearance A Creatinine Clearance Calculator is able to provide a reasonable estimate of your kidneys’’ ability to filter waste from your blood. This calculation uses serum Creatinine, age, weight, sex and theCockcroft-Gault formula. You typically see results expressed in the form of milliliters per minute (mL/min).
When muscle tissue breaks down, it releases creatinine into the bloodstream as a waste product, and the kidneys filter this creatinine out from the blood. For this reason, blood serum levels of creatinine will be included among variables for a calculation of kidney clearance. The Cockcroft-Gault equation calculates estimated creatinine clearance by using serum creatinine level, along with the patient's body weight and age.
The calculation is an estimate and does not reflect the exact amount of creatinine cleared by the kidney. In clinical use, this value may be interpreted in context with other lab data, medication, medical conditions and individualpatient factor.
The traditional Cockcroft-Gault equation for estimated creatinine clearance is:
Creatinine Clearance = [(140 − age) × weight] ÷ [72 × serum creatinine]
For the traditional equation, the result is multiplied by 0.85 for females.
This equation yields an approximated creatinine clearance value in around mL/min for the noted inputs in this case.
When weight can be critical to the output, the calculator should indicate its input weight scheme. In certain clinical uses, it's sometimes desirable to use other than actual body weight.
Consider a hypothetical 60-year-old male weighing 70 kg with a serum creatinine of 1.0 mg/dL.
Using the Cockcroft-Gault equation:
[(140 − 60) × 70] ÷ [72 × 1.0]
= 5,600 ÷ 72
≈ 77.8 mL/min
This article is illustrative and provides only the math calculation, not intended for clinical diagnosis, drug dosage or indication, or renal status.
A creatinine clearance is an estimate of the rate at which creatinine is cleared from the body. It is usually expressed in mL/min. The result should be interpreted in conjunction with the individual's age, size, serum creatinine level, clinical condition and the reason for the calculation.
A value that has been calculated should not be tagged as normal/ abnormal based on one normal cutoff (i.e. universally defined). Kidney function differs with age and other patient-related factors, and various decisions may require different assessment tools.
Remember to differentiate between creatinine clearance and eGFR: As creatinine clearance can be estimated using the Cockcroft-Gault equation this is also not a substitute for more contemporary estimated glomerular filtration rate equation models, for example the CKD-EPI equation. both use function the kidneys use to filter waste from the blood in order to predict an estimate but are calculated differently.
Creatinine clearance and estimated glomerular filtration rate are related but distinct measures.
| Measure | What It Represents | Common Calculation Context |
|---|---|---|
| Creatinine clearance | Estimated clearance of creatinine | Traditionally calculated with Cockcroft-Gault in certain clinical applications |
| eGFR | Estimated glomerular filtration rate | Calculated using equations such as CKD-EPI from laboratory and demographic variables |
You shouldn't use these values interchangeably simply because they are both measures of kidney filtration that might appear on your test. Follow whichever of these calculation methods-or, more importantly, whoever-tells you to use it.
Attention must also be given to the weight required by the equation - an actual body weight is not mandatory to all of the people within the Cockcroft-Gault equation, at times it may be acceptable to use idéal or adjusted body weight depending on individual patients and physical characteristics.
This is most relevant where the size of a patient’s body is very different from that expected for their height. So you could get a different answer depending on the weight method you select. If using the calculator for determining the correct dosage for a medication, you should use the weight method appropriate for your setting (according to your local clinical guideline, relevant department protocol etc.)
Serum creatinine is commonly reported in mg/dL in the United States. Some laboratories use µmol/L. These units are not interchangeable without conversion.
A commonly used conversion is:
Creatinine in mg/dL = Creatinine in µmol/L ÷ 88.4
A result of 88.4 mol/L for serum creatinine would be roughly equivalent to 1.0 mg/dL. Always check the laboratory unit before inputting the value into the calculator.
Glomerular filter rate(GLFR)-this is an approximate measure of the rate at which serum creatinine is cleared from the blood. This can be estimated by the Cockcroft-Gault equation usingage, weight, serum creatinine and sex.
Traditional Cockcroft-Gault equation = (140 age) weight / 72 serum creatinine. multiply by 0.85 to derive correct for females to traditional cockcroft-gault
The result is often given in milliliters per minute (mL/min). Serum creatinine is typically keyed into the equation as mg/dL when using the standard formula Cockcroft Gault.
Only if the calculator takes the value as mol/L. Otherwise, you'll want to get it into mg/dL: mol/L / .00884 (for example, onemol / L for creatinine is 88.4 mg / dL ).
No. In Cockcroft-Gault estimates, creatine clearance (eCrCl) is generated; CKD-EPI uses the same components as Cockcroft-Gault to produce the glomerular filtration rate (eGFR).
Body weight is also one of the variables included in the Cockcroft-Gault formula. That is, if one of actual weight, ideal weight or another weight is substituted for actual weight and can lead to differences of estimated outcome, asbody mass differs from average.
Use a recent value from a reliable measurement source and verify the unit before calculating. Discuss unexpected or abnormal results with a qualified clinician rather than changing treatment based on the calculator.
Serum creatinine is among the most impactful of the components of the Cockcroft-Gault equation. As it is found in the denominator of the equation a higher serum creatinine typically indicates a lower estimated creatinine clearance, assuming the other factors remain the same.
| Serum Creatinine | Age | Weight | Sex | Estimated Creatinine Clearance |
|---|---|---|---|---|
| 0.8 mg/dL | 60 years | 70 kg | Male | 97.2 mL/min |
| 1.0 mg/dL | 60 years | 70 kg | Male | 77.8 mL/min |
| 1.2 mg/dL | 60 years | 70 kg | Male | 64.8 mL/min |
| 1.5 mg/dL | 60 years | 70 kg | Male | 51.9 mL/min |
| 2.0 mg/dL | 60 years | 70 kg | Male | 38.9 mL/min |
These mathematical calculations use the age of the patient and the older body weight formula Cockcroft and Gault for an 70kg weight. They are NOT clinical ranges and should not be used to form a patients diagnosis or treatment plan.
A computed creatinine clearance will vary whenever anything within the calculation changes. If the formula itself is still being followed exactly, a change in a calculation made at that time involving serum creatinine, age, weight, or the relevant sex correction factor can cause results to vary from day to day.
It's sometimes employed when the drug instructions or clinical protocol indicates the use of theCockcroft-Gaultformula for dose calculations. Nevertheless, kidney function parameter is not consistently measured the same way for all drug or the dose threshold might be set different for different drugs.
A result that is obtained from a calculator should not, on its own, be relied on as an indicator to start, increase, decrease, or stop a medication dosage. The calculation method appropriate to the individual medication and the patient is also based upon the individual clinical situation.
Assumed relationship The standard calculation is based on an relationship of serum creatinine production on characteristics which will not be the same in all individuals. Thus clinical expertise may be required when the characteristics differ widely to those which underpinned the calculation.
These factors don't prevent calculation all together, but they make the use and interpretation of the outcome more uncertain.
Estimating a Cockcroft-Gault score is just an estimate. Measured creatinine clearance might be done by collecting urine over a specific time plus measuring serum creatinine level. Neither method is quite the same and either can give a range of values rather than a precise result.
What most people who use their calculators the most should be aware of is that inputting in the appropriate lab and demographical details into your formula does not equate to kidney filtration being measured.
If the result of a creatinine clearance measurement is used to help explain or interpret a laboratory test, evaluate kidney function, or make a decision about a prescription drug, report the result and compare it with a copy of the laboratory report, history, medications, body characteristics, and other pertinent clinical information with an experienced practitioner in appropriate licensure.
A single calculated value should not be used to infer a renal disease and medication changes should not be made without the input of a trained clinician.