The formula presumes normal muscle mass and function and will be inaccurate in cases of significant muscle disease, including muscle wasting.
- Uses the Cockcroft and Gault Creatinine Clearance which is the gold standard after almost 40 years.
- May have inaccuracies from variations in body composition among patients.
- Those who understand potential sources of error can adjust accordingly.
- Creatinine clearance is still used as the standard for drug dosing, instead of GFR.
- Creatinine is a waste product that is produced continuously during normal muscle breakdown.
- The kidneys filter creatinine from the blood into the urine, and reabsorb almost none of it.
- The amount of blood cleaned of creatinine by your kidneys is called the creatinine clearance.
- Creatinine clearance in a healthy young person is about 95 ml/min for women/120 ml/min for men.
- This means that each minute, that person's kidneys clear 95-120 mL of blood free of creatinine.
- The glomerular filtration rate (GFR) can vary depending on age, sex, and size.
- Generally, the creatinine clearance is a good estimation of the glomerular filtration rate.
- For the calculation you need to know the patients
- Height may be used
- Creatinine Clearance = [[140 - age(yr)]*weight(kg)]/[72*serum Cr(mg/dL)] (multiply by 0.85 for women).