Why Your EGFR Trend MattersEGFR is not an exact number, and it can bounce around a little from test to test. If one test shows an eGFR of 47, the next one comes back at 44, and a later test shows 48, that’s okay because the pattern consists of numbers in the same range, which means the eGFR is stable, he says. “What’s concerning is if we see an ongoing trend of worsening eGFR over months or years,” says Johnson. If kidney function is going down by 1 percent to 3 percent per year consistently, that suggests disease progression, and treatment is needed to slow things down, he says. “But the medications available today are designed to change this trajectory and slow the rate of progression,” Parikh says.