How Does Race Affect Results on the EGFR Test?

Race is an important criterion because the equation most widely used in determining the estimated glomerular filtration rate, or eGFR, is currently only validated in Caucasian and African-American patients, states the National Kidney Disease Education Program. The difference between eGFR values for African and non-African-Americans is approximately 20 percent, according to Mayo Clinic.

In 2012, the National Kidney Foundation studied the accuracy of the equation used in the modification of diet in renal disease study, which is the equation most used for estimating the glomerular filtration rate in kidney disease sufferers. It concluded that the MDRD equation leads to acceptable estimations of the GFR in both younger and older Caucasian patients, as explained by PubMed.

The MDRD equation is limited for estimating GFR in patients whose ethnicity is not well represented in validation groups, such as people over age 70, African-Americans with higher GFR levels and minorities other than African-Americans, cautions the National Kidney Disease Education Program. The Third National Health and Nutrition Examination Survey, published in 2007, found that Hispanic and African-American participants nationwide typically presented metabolic abnormalities, leading the authors to suggest that only one eGFR value might not be an accurate indicator of kidney disease for minority patients. Validation studies are in progress on other populations, reports Mayo Clinic. These validation studies may find that new or modified equations are necessary for minority subgroups, such as Hispanics.