Reference or Target Ranges

• See individual test components for reference ranges.

EGFR- ≥60 mL/min/1.73m2

The formula for the 2021 CKD-EPI creatinine equation is:

• eGFR = 142 × min(SCr/κ,1)α × max(SCr/κ,1)-1.200 × 0.9938Age × 1.012 [if female] 

This equation uses standardized serum creatinine (SCr), a kappa value (κ) based on sex (0.7 for females, 0.9 for males), an alpha value (α) based on sex (-0.241 for females, -0.302 for males), and age in years. "min" and "max" in the formula indicate the minimum and maximum of SCr/κ or 1, respectively. 

• eGFR not calculated for age < 18 years
• Clinical practice guidelines suggest the use of serum cystatin C as a confirmatory test for eGFR 45-59 ml/min/1.73m2 in adults who do not have markers of kidney disease; eGFR may be less accurate in this range.