Glomerular Filtration Rate

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Contents 1 More Specific Terms 2 Introduction 3 Reference-interval 4 Clinical-significance 5 Methods 6 More General Terms 7 Additional Terms 8 References

More Specific Terms

• glomerular filtration rate blacks
• glomerular filtration rate females

Introduction

• Estimated from creatinine clearance

Reference-interval

• 75-130 mL/min/1.73 m2

Clinical-significance

• < 60 mL/min/1.73 m2 consistent with chronic kidney disease
• < 15 mL/min/1.73 m2 consistent with renal failure
• glomerular filtration begins to decline in the 4th decade of life

Methods

• radionuclide kidney clearance scanning is the gold standard for estimation of glomerular filtration rate
• clearance of inulin, iothalamate, DPTA & creatinine are measures of glomerular filtration rate
• creatinine clearance is most commonly used to estimate glomerular filtration rate

• the creatinine clearance is determined by a 24 hour urine for creatinine along with serum creatinine according to the following equation:

*               Creatinine [urine] (mg/dL) x volume (mL) 
*               ---------------------------------------- 
*               Creatinine [serum] (mg/dL) x minutes

• creatinine clearance overestimates glomerular filtration because of tubular secretion of creatinine
  
• the creatinine clearance is often estimated using a patient's age, weight & sex according to the Cockcroft-Gault equation.

• The Cockcroft-Gault estimate formula for males is:

<br>  
*       (140 - age in years) x lean body weight in kg 
* GFR =  --------------------------------------------- 
*              serum creatinine in mg/dL x 72 

• for females, use the above formula & multiply by 0.85
• other methods include

• Modification of Diet in Renal Disease formula (MDRD formula)
• Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI formula) [4]

• Also see: National Kidney Foundation's renal function calculator [4]

More General Terms

• laboratory analysis

Additional Terms

• creatinine clearance

References

1. Medical Knowledge Self Assessment Program (MKSAP) 15, American College of Physicians, Philadelphia 2009
2. Mayo Internal Medicine Board Review, 1998-99, Prakash UBS (ed) Lippincott-Raven, Philadelphia, 1998, pg 620
3. Prescriber's Letter 12(7): 2005 Calculating Renal Function Detail-Document#: [1] (subscription needed) [2]
4. Matsushita K et al. Comparison of risk prediction using the CKD-EPI equation and the MDRD study equation for estimated glomerular filtration rate. JAMA 2012 May 9; 307:1941 PMID: [3]
   - Kalantar-Zadeh K and Amin AN. Toward more accurate detection and risk stratification of chronic kidney disease. JAMA 2012 May 9; 307:1976. PMID: [4]
5. National Kidney Foundation's renal function calculator [5]

glomerular filtration rate (GFR)