GFR


Sunquest Code:CREA  
Epic Code:LAB5916Epic Name:GFR ESTIMATED
Synonyms:Glomerular Filtration Rate, Calculation; Estimated Creatinine Clearance
Methodology:Calculation using IDMS-traceable study equation on every serum creatinine with the following exceptions: patient is <16 years, sex unknown, or creatinine is <0.05 mg/dL.
CPT Code:82565


Collection Instructions

Specimen:Blood
Container:Green (lithium heparin, gel) (Green (sodium heparin, no gel), Red (no gel), Red or gold (gel))


Processing and Shipping

Test Performed at or Referral Lab Chemistry  (Fairview Range - FRMC, UMMC-East Bank, Fairview Lakes - FLMC, Fairview Ridges - FRH, Fairview Northland - FNMC, Fairview Southdale - FSH, UMMC/UMMCH-West Bank)


Interpretive

Reference Range:

>60 mL/min/1.73m2. We suggest greater than 80 mL/min/1.73m2 as being compatible with normal renal function. Values less than 80 mL/min/1.73m2 may indicate impaired renal function, with values between 60 to 80 mL/min/1.73m2 as borderline. However, all values should be interpreted with respect to the patient’s clinical status and age. Please note that GFR declines with age in healthy people

 

 

Limitations:Use of the IDMS-traceable MDRD Study equation to assess kidney damage is only a screening test and not completely sensitive nor specific for detecting decreased kidney disease. Clinicians should consider all aspects of the patient's clinical condition in interpreting test results for guiding further diagnosis and management, especially in the evaluation of individuals with mild disease (GFR of 60 to 89 mL/min/1.73m2) (NDOQI Guidelines)
Use:

Glomerular filtration rate (GFR) traditionally is considered the best overall index of renal function in health and disease. A low or decreasing GFR is a good index of chronic kidney disease. Because GFR is difficult to measure in clinical practice, formulas have been developed to estimate creatinine clearance. The Cockcroft and Gault formula1 has been widely used; however, more recently equations have been developed from the Modification of Diet in Renal Disease (MDRD) Study that improve the prediction of GFR from serum creatinine concentration2-4. The abbreviated MDRD Study Equation is an equation for estimating GFR based on a patient’s creatinine, age, sex and whether or not they are African-American 3,4.

 

Abbreviated MDRD Study Equation:

 

Estimated GFR (ml/min/1.73m2)

=      175 x (SCr)-1.154 x (Age)-0.203 x (0.742 if female) x (1.210 if African-American)

 

=      exp[5.228 - (1.154 x ln(SCr)) – (0.203 x ln(Age)) – (0.299 if female) + (0.192 if African-American)]

 

SCr = serum creatinine

exp = e raised to the power of a given number

ln = natural logarithm of a number

 

References:

1. Cockcroft DW, Gault MH. Prediction of creatinine clearance from serum creatinine. Nephron 16:31-41 (1976).

2. Levey AS, Bosch JP, Lewis JB, Greene T. A more accurate method to estimate glomerular filtration rate from serum creatinine: a new prediction equation. Ann Intern Med 130:461-70 (1999).

3. Levey AS, Grene T, Kusek JW, Beck GJ. A simplified equation to predict glomerular filtration rate from serum creatinine (Abstract). J Am Soc Nephrol 11:A0828 (2000).

4. National Kidney Foundation DOQI. Part 5. Evaluation of laboratory measurements for clinical assessment of kidney disease. Am J Kidney Dis 39:S76-92 Suppl (2002).

 

 



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