As your body makes it, it’s filtered through your kidneys and expelled in urine. Your kidneys’ ability to handle creatinine is called the creatinine clearance rate, and this helps estimate how fast blood is moving through your kidneys, called the glomerular filtration rate (GFR).
How is GFR related to creatinine?
GFR is related inversely and nonlinearly to serum creatinine. Age, gender, and race all affect muscle mass and, in turn, serum creatinine.
Is creatinine used to calculate GFR?
How to calculate your GFR. Estimating GFR begins with a simple serum creatinine blood test. If you’re using our GFR calculator, your eGFR is calculated using the results of your blood test, along with your age, ethnicity, and gender.
Why is creatinine inversely proportional to GFR?
Men have more muscle mass than females. Hence, for any man the blood creatinine will be higher for any level of kidney function (estimated glomerular filtration rate) than a woman, because the woman has proportionally less muscle to produce the blood level of creatinine.
What is the relationship between GFR and creatinine clearance?
Creatinine clearance ( CrCl ) is an estimate of Glomerular Filtration Rate ( GFR ); however, CrCl is slightly higher than true GFR because creatinine is secreted by the proximal tubule (in addition to being filtered by the glomerulus). The additional proximal tubule secretion falsely elevates the CrCl estimate of GFR.
Which is used to estimate GFR?
Glomerular filtration rate (GFR) is the best overall index of kidney function. Normal GFR varies according to age, sex, and body size, and declines with age. The National Kidney Foundation recommends using the CKD-EPI Creatinine Equation (2021) to estimate GFR.
Why the serum creatinine and GFR estimation equations should only be used in patients with stable kidney function?
Creatinine-based estimating equations may not be suitable for all populations. Creatinine-based estimates of kidney function are only useful when renal function is stable; serum creatinine values obtained while kidney function is changing will not provide accurate estimates of kidney function.
What is GFR used for?
Glomerular filtration rate (GFR) is a calculation that determines how well the blood is filtered by the kidneys, which is one way to measure remaining kidney function. GFR is also used to find the stage of chronic kidney disease.
What is the difference between GFR and eGFR?
GFR is Glomerular Filtration Rate and it is a key indicator of renal function. eGFR is estimated GFR and is a mathematically derived entity based on a patient’s serum creatinine level, age, sex and race.
How glomerular filtration is estimated?
Most often the glomerular filtration rate is estimated by measuring another substance. Many estimated glomerular filtration rate (eGFR) tests use a formula based on the levels of creatinine, a waste product produced by the body’s muscles, in the blood.
Why is creatinine clearance higher than GFR?
Creatinine clearance exceeds GFR because creati- nine is secreted by the proximal tubule as well as filtered by the glomerulus. Creatinine clearance can be measured from serum creatinine and cre- atinine excretion, or estimated from serum cre- atinine using estimating equations.
What is creatinine GFR?
What about creatinine? GFR is an equation that uses your creatinine, age, race and gender to see how well your kidneys are working. Creatinine is the level of muscle waste in your blood stream. Kidneys are supposed to filter out this waste into urine.
Why is creatinine clearance still not an absolute equivalent of GFR?
A significant disadvantage of creatinine clearance is that it becomes less accurate as GFR drops. This is due to the fact that renal tubules secrete a small amount of creatinine into the urine (in addition to that which is filtered).