Glomerular Filtration Rate, Estimated (eGFR)

Glomerular Filtration Rate, Estimated (eGFR)

Number

100768

CPT

82565

Synonyms

eGFR ; Estimated Glomerular Filtration Rate ; GFR, Estimated

Test Includes

Creatinine, serum; eGFR calculation

Specimen

Serum

Volume

1 mL

Minimum Volume

0.5 mL

Container

Gel-barrier tube or transport tube

Collection

Separate serum from cells within 45 minutes of collection.

Storage Instructions

Maintain specimen at room temperature.

Causes for Rejection

Hemolysis; improper labeling

Reference Interval

Male: 60-137 mL/minute
Female: 60-128 mL/minute

Note: The estimated GFR is multiplied by 1.212 in the cases of patients who are African-American.

Use

The estimated glomerular filtration (eGFR) provides an assessment of the filtering capacity of the kidney. The eGFR is calculated from a serum creatinine using the MDRD equation. Aside from the serum creatinine, other variables required for the equation are sex, age, and race. The eGFR has been shown to be more accurate in estimating the glomerular filtration rate than a 24-hour urine collection for creatinine clearance. Among patients with chronic kidney disease (CKD), the eGFR is instrumental in determining the stage of disease according to the K/DOQI CKD classification. See table. Association of Glomerular Filtration Rate (GFR) and Staging of Kidney Disease¹

GFR (mL/min/1.73 m²⁾	With Kidney Damage	Without Kidney Damage
90	Stage one	Normal
60-89	Stage two	Decreased GFR
30-59	Stage three	Stage three
15-39	Stage four	Stage four
<15 (or dialysis)	Stage five	Stage five
¹Each stage assumes the associated GFR level has been in effect for at least 3 months. Stage 1-5 with or without kidney disease indicates chronic kidney disease.

Limitations

The equation is not applicable for pediatric patients, nor in those >70 years of age. The following conditions may alter the eGFR result: extremes in body size, severe malnutrition or obesity, skeletal muscle disease, paraplegia or quadriplegia, vegetarian diet, and rapidly changing kidney function.

Methodology

Kinetic

Additional Information

While a normal GFR in young adults is ~120-130 mL/minute/1.73 m², it declines with age, and values <60 mL/minute/1.73 m² for 3 or more months is defined as CKD. To determine the presence of proteinuria, low eGFR results may be followed up with albumin:creatinine ratio. An albumin:creatinine ratio >30 mg/g would be indicative of kidney damage.

References

Cockcroft DW, Gault MH. Prediction of Creatinine Clearance From Serum Creatinine, Nephron, 1976; 16:31-41.

Coresh J, Astor BC, Greene T, et al. Prevalence of Chronic Kidney Disease and Decreased Kidney Function in the Adult U.S. Population: Third National Health and Nutrition Examination Survey, Am J Kidney Dis, 2003; 41(1):1-12.

Levey AS, Beto JA, Coronado BE, et al. Controlling the Epidemic of Cardiovascular Disease in Chronic Renal Disease: What Do We Know? What Do We Need to Learn? Where Do We Go from Here? National Kidney Foundation Task Force on Cardiovascular Disease, Am J Kidney Dis, 1998; 32(5):853-906.

Levey AS, Bosch JP, Lewis JB, et al. A More Accurate Method to Estimate Glomerular Filtration Rate From Serum Creatinine: A New Prediction Equation. Modification of Diet in Renal Disease Study Group, Ann Intern Med, 1999; 130 (6):461-470.

Levey AS, Greene T, Kusec JW, et al. A Simplified Equation to Predict Glomerular Filtration Rate From Serum Creatinine, J Am Soc Nephrol, 2000; 11:A0828.

National Kidney Foundation. Chronic Kidney Disease: Developing a Clinical Action Plan, New York, NY; www.kidney.org/professionals/doqi/action_plan_web.html; accessed: Jan, 2003.

National Kidney Foundation. K/DOQI Clinical Practice Guidelines for Chronic Kidney Disease: Evaluation, Classification, and Stratification, Am J Kidney Dis, 2002; 39(Suppl 1):S1-S266.

Perrone RD, Madias NE, Levey AS. Serum Creatinine as an Index of Renal Function: New Insights Into Old Concepts, Clin Chem, 1992; 38(10):1933-1953.

United States Renal Data System. Excerpts From the 2000 U.S. Renal Data System Annual Data Report: Atlas of End-Stage Renal Disease in the United States, Am J Kidney Dis, 2000; 36:S1-S279.