This is a discussion of Creatinine Clearance test , which is one of the Kidney function tests .
We are going to discuss its normal and abnormal values, methods and equations of calculation and its significance .
• It is a method to measure GFR approximately.
• It is the volume of plasma cleared from creatinine / min. = U x V / P
U = urine creatinine mg/dl.
V = voIume of urine / min. = Urine volume in 24hrs / 1440
P = plasma creatinine mg/dl.
• Normal Value
90-140 ml/min for males, 80-125 ml/min for females)
• Serum creatinine starts elevation when creatinine clearance < 25%-30%.
• The glomerular filtration rate (GFR) varies with age and sex but is approximately 120-130 ml/min/1.73 m2 surface area.
It can be measured by renal scan using Diethylene triamine penta-acetic acid labeled with technetium (99mTc-DTPA), it is more accurate than creatinine clearance.
- GFR 35-50% of normal is sufficient to maintain the patient symptom-free, at GFR 20-35% azotemia occurs with initial manifestations of renal insutticiency, at GFR < 20-25% the patient develops overt rena! failure.
The calculated clearance should be reduced by 15% for women.
We are going to discuss its normal and abnormal values, methods and equations of calculation and its significance .
• It is a method to measure GFR approximately.
• It is the volume of plasma cleared from creatinine / min. = U x V / P
U = urine creatinine mg/dl.
V = voIume of urine / min. = Urine volume in 24hrs / 1440
P = plasma creatinine mg/dl.
• Normal Value
90-140 ml/min for males, 80-125 ml/min for females)
• Serum creatinine starts elevation when creatinine clearance < 25%-30%.
• The glomerular filtration rate (GFR) varies with age and sex but is approximately 120-130 ml/min/1.73 m2 surface area.
It can be measured by renal scan using Diethylene triamine penta-acetic acid labeled with technetium (99mTc-DTPA), it is more accurate than creatinine clearance.
- GFR 35-50% of normal is sufficient to maintain the patient symptom-free, at GFR 20-35% azotemia occurs with initial manifestations of renal insutticiency, at GFR < 20-25% the patient develops overt rena! failure.
Calculation of creatinine clearance (Cockcroft & Gault equation)
The calculated clearance should be reduced by 15% for women.