BLATIMORE— Assessing glomerular filtration rate (GFR) using kidney filtration markers in blood is the standard means for determining kidney function, diagnosing kidney disease and measuring its progression.

A higher filtration rate indicates healthy kidney function, while a lower rate points to various stages of kidney disease. A new study led by researchers at the Johns Hopkins Bloomberg School of Public Health found that the new CKD-EPI equation for calculating GFR is a better predicator of risk for kidney disease and death compared to the most widely used method.

The findings suggest that switching to the CKD-EPI equation for calculating GFR could focus efforts more efficiently, and improve assessment of patient future risk and treatment of kidney disease. The study is published in the May 9 edition of the Journal of the American Medical Association (JAMA).

GFR is calculated using a patient’s age, sex, race and serum creatinine level, which is a measure of a molecular waste product in blood. More than 92 percent of labs in the U.S., use the MDRD Study equation developed in 1999 to estimate GFR. The test is conducted more than 300 million times per year. The CKD-EPI equation uses the same data as the MDRD Study equation to estimate GFR.

For the study, GFR estimates were broken into six categories, which correspond with various stages of kidney disease. A GFR of 90 or greater indicates healthy kidney function, while a GFR of 15 and lower indicates kidney failure and initiation of dialysis for many patients. The researchers compared GFR estimates using both calculation methods from data covering a diverse study population of more than 1 million participants.

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