Creatinine Clearance Flashcards
What is creatinine?
Creatinine is a normal by-product of muscle contractions which becomes a chemical waste product filtered from the blood by the kidneys.
It is released at a constant rate by the body.
Serum creatinine (a blood measurement) is an important indicator of kidney health, because it is an easily measured byproduct of muscle metabolism that is excreted unchanged by the kidneys.
How is creatinine produced?
Via a biological system involving creatine, creatine phosphate and adenosine triphosphate.
Explain how creatinine is removed by the body
Creatinine is removed by the body primarily by the kidneys via glomerular filtration.
Little or no tubular reabsorption occurs (movement from tubular lumen back into blood).
If the filtration of the kidney is deficient, blood creatinine will rise. Therefore, creatinine concentrations in blood and urine may be use to calculate the creatinine clearance which approximately correlations with the GFR.
Why is creatinine the best indicator of renal function?
It is filtered in the renal corpuscle but does not undergo reabsorption. It does undergo a small amount of secretion, therefore it slightly overestimates the GFR.
Creatinine is a useful indicator of renal health because it is excreted in the urine as an unchanged and easily measured by-product of muscle metabolism. In a healthy kidney, little or no creatinine is reabsorbed, whereas, in kidney disease, the creatinine concentration in the blood may increase.
What would happen to serum urea and serum creatinine levels in kidney failure?
Both would rise if the kidneys are not functioning properly as they would usually be filtered and excreted in the urine.
Would an increase in creatinine concentration in the blood indicate a higher or lower GFR?
Lower GFR
What is Creatinine clearance?
What does a decreased/low creatinine clearance signify?
The creatinine clearance test helps provide information about how well the kidneys are working. The test compares the creatinine level in urine with the creatinine level in blood.
Lower Creatinine Clearance suggests less is being excreted and therefore impaired renal function.
