eGFR Calculation for Black Women
Use the 2021 CKD-EPI creatinine equation without any race coefficient for all Black women. 1, 2
Primary Recommendation
The NKF-ASN Task Force issued a strong recommendation in 2022 for immediate implementation of the race-free CKD-EPI creatinine equation (CKD-EPIcr_R) across all U.S. laboratories, explicitly removing race from both calculation and reporting. 1 This unified approach applies to all adults regardless of self-identified race and represents the current standard of care. 1, 2
Why This Matters for Black Women Specifically
Black women face compounded disadvantage from race-based equations because obesity prevalence is highest in this demographic, and indexed eGFR approaches systematically underestimate true GFR in patients with obesity, leading to medication underdosing and delayed interventions. 1
The old race-based equation systematically overestimated eGFR in Black patients by approximately 16%, delaying CKD diagnosis, nephrology referrals, transplant eligibility, and access to kidney-protective medications. 2, 3
Removing the race coefficient identifies approximately 2 million more Black adults with CKD and increases the number meeting transplant referral thresholds by 290,000 individuals (a 29% increase). 2
Confirmatory Testing Strategy
For Black women at risk for or with established CKD, add cystatin C measurement and use the 2021 CKD-EPI creatinine-cystatin C equation without race (CKD-EPIcr-cys_R). 1, 2
Combining creatinine and cystatin C provides greater accuracy than either marker alone and completely eliminates the need for race-based adjustments. 1, 2
Cystatin C is particularly valuable in patients with low muscle mass, where creatinine-based estimates are less reliable. 2
Critical Implementation Points
What NOT to Do
Never report two eGFR values (one with race, one without) or label them as "high muscle mass" versus "low muscle mass"—the Task Force found no evidentiary basis for dual reporting, which adds subjectivity and confusion. 2
Do not use the race coefficient under any circumstances, even if the patient self-identifies as Black or African American. 1, 2
Laboratory Reporting Standards
Report eGFR using the race-free 2021 CKD-EPI equation. 2
Display serum creatinine values to two decimal places for improved precision. 2
For medication dosing decisions, use non-indexed eGFR values (mL/min) rather than indexed values (mL/min/1.73 m²). 1, 2
In Black women with obesity, strongly consider de-indexing GFR for medication dosing because indexed eGFR may substantially underestimate true GFR, risking therapeutic underdosing. 1, 2
Clinical Decision-Making Algorithm
Do not base major clinical decisions on a single eGFR result—confirm with repeat testing and monitor trends over time. 1, 2
Incorporate albuminuria assessment alongside eGFR to complement kidney function evaluation. 2
For critical decisions (transplant eligibility, chemotherapy dosing, nephrotoxic drug initiation), use confirmatory testing with cystatin C-based equations or direct clearance measurements. 1, 2
When high precision is required, consider direct GFR measurement using exogenous filtration markers. 2
Common Pitfalls to Avoid
Relying on old race-based equations creates systematic disadvantages for Black women in accessing nephrology care, transplant evaluation, and kidney-protective therapies (ACE inhibitors, SGLT2 inhibitors). 2
Using the race coefficient actually delays diagnosis in Black patients—the race-free equation better correlates with measured GFR in this population. 3, 4
Ignoring body habitus when interpreting indexed eGFR in obese patients leads to underestimation of true kidney function and potential medication errors. 1
Evidence Quality and Consensus
The 2022 NKF-ASN Task Force recommendation represents the highest-quality guideline evidence available, published in the American Journal of Kidney Diseases after a comprehensive 10-month deliberative process involving expert testimony, patient input, and systematic evidence review. 1 This recommendation is endorsed by KDOQI and explicitly stated in KDIGO Practice Point 1.2.4.2. 2 The consensus strongly prioritizes reducing differential bias and promoting health equity over preserving statistical properties of older race-based equations. 2