Creatinine Clearance Calculator

Creatinine clearance is a measure of how well your kidneys are filtering waste from your blood. Creatinine is a waste product produced by your muscles and filtered out by your kidneys. If your kidneys aren't working properly, creatinine builds up in your blood. This test helps doctors assess kidney function and detect early signs of kidney disease.

A normal eGFR (estimated Glomerular Filtration Rate) is typically 90 mL/min/1.73m² or higher. Values between 60-89 may indicate mild kidney function loss, while values below 60 for 3 months or more suggest chronic kidney disease. However, eGFR naturally declines with age, so your doctor will interpret results in the context of your age and overall health.

The single most important step is to share and discuss this result with your doctor or another qualified healthcare provider. They can confirm the result with their own tests, investigate the cause of any potential issues, and work with you to create a health plan. It is critical that you do not make any changes to your diet, lifestyle, or medications based solely on the result from this or any other online calculator.

While existing kidney damage usually cannot be reversed, a healthy lifestyle is absolutely essential for protecting your remaining kidney function and slowing the progression of any disease. Key strategies include managing blood pressure and blood sugar, eating a balanced, kidney-friendly diet (which may involve reducing animal protein, sodium, and sugar), staying well-hydrated, and avoiding overuse of certain medications like NSAID pain relievers. Always work with your doctor or a registered dietitian to develop a plan that is safe and effective for your specific situation.

The amount of creatinine your body produces is directly related to your muscle mass, which naturally varies with age and typically differs between biological sexes. By including your age and sex in the calculation, the eGFR formula can provide a much more accurate and personalized estimate of your kidney function than looking at the creatinine blood level alone.

"Creatinine Clearance" (CrCl) is an older method of estimating kidney function. It was either calculated using the Cockcroft-Gault formula or directly measured with a cumbersome 24-hour urine collection process. "eGFR" (estimated Glomerular Filtration Rate) is the modern standard. It is calculated using a more accurate formula (like the 2021 CKD-EPI equation) from a simple blood test. For assessing overall kidney function, eGFR is now considered the more reliable and accurate measure. This calculator focuses on providing your eGFR to give you the most current and clinically relevant information.

The 2021 CKD-EPI Creatinine Equation is the most current and recommended formula for estimating glomerular filtration rate (eGFR). It was developed by the Chronic Kidney Disease Epidemiology Collaboration and removes race-based variables to improve equity in care. This equation is more accurate than older formulas and is the gold standard for kidney function assessment.

Older formulas like MDRD and Cockcroft-Gault have limitations that make them less reliable for modern clinical use. The MDRD equation included race-based variables that have been removed from current guidelines. The Cockcroft-Gault formula from 1973 was developed before modern laboratory standards and can significantly overestimate kidney function, potentially leading to incorrect medication dosing decisions.

Chronic Kidney Disease (CKD) stages classify kidney function based on eGFR values. Stage 1 (≥90) indicates normal function with possible kidney damage signs. Stage 2 (60-89) shows mild function loss. Stage 3a (45-59) and 3b (30-44) represent mild to severe function loss. Stage 4 (15-29) indicates severe loss, and Stage 5 (<15) represents kidney failure requiring dialysis or transplant.

The Cockcroft-Gault formula is primarily used for medication dosing adjustments in patients with kidney disease, particularly for drugs that are renally eliminated. However, it should be used with caution as it can overestimate kidney function. The 2021 CKD-EPI equation is preferred for general kidney function assessment and CKD staging.

This calculator accepts both mg/dL (common in the US) and µmol/L (common internationally). The calculator automatically converts µmol/L to mg/dL using the standard conversion factor of 88.4. Use the units that match your laboratory results for the most accurate calculation.

The 2021 CKD-EPI equation is highly accurate for most patients with stable kidney function. However, these are estimates and should be interpreted in clinical context. Factors like muscle mass, diet, medications, and acute illness can affect creatinine levels and eGFR accuracy. Always consult with healthcare professionals for clinical decisions.

No, this calculator is designed for adults (age 18 and older). The formulas used are validated for adult populations. Pediatric kidney function assessment requires different equations that account for age-related changes in muscle mass and body composition. Consult with pediatric nephrology for children's kidney function assessment.

Creatinine levels can be influenced by muscle mass, diet (especially meat consumption), medications (like trimethoprim, cimetidine), dehydration, and acute illness. High muscle mass can increase creatinine without indicating kidney disease, while low muscle mass can mask kidney dysfunction. This is why eGFR calculations include age and sex variables.

The frequency depends on your health status and risk factors. Healthy adults may only need annual screening. Those with diabetes, hypertension, or family history of kidney disease should be tested more frequently. Patients with known CKD may need testing every 3-6 months. Always follow your healthcare provider's recommendations for monitoring frequency.