Box 3.
Inventory of Possible Approaches to Estimating and Reporting GFR for General Use
| Creatinine Used as Biomarker | Noncreatinine Biomarker Used |
|---|---|
| Estimation and reporting with creatinine and race using existing equations | Estimation with cystatin C, creatinine, and race using existing equations |
| (1) eGFRcr (MDRD or CKD-EPI) (age, sex, race) with “Black” estimate reported for self-identified African Americans and “non-Black” estimate reported for persons from other communities8,10,a | (13) eGFRcr-cys (CKD-EPI) (age, sex, race) with “Black” estimate reported for self-identified African Americans and “non-Black” estimate reported for persons from other communities12 |
| Estimation with creatinine and race using existing equations but reporting without specification of race | Estimation with cystatin C, creatinine, and race using existing equations but reporting without specification of race |
| (2) eGFRcr (CKD-EPI) (age, sex, race) with “Black” estimate reported as “high muscle mass,” and “non-Black” estimate reported as “low muscle mass”a | (14) eGFRcr-cys (CKD-EPI) (age, sex, race) with “Black” estimate reported as “high muscle mass,” and non-Black estimate reported as “low muscle mass” |
| (3) eGFRcr (CKD-EPI) (age, sex, race) with “Black” estimate reported as “high value,” and “White” reported as “low value”a | (15) eGFRcr-cys (CKD-EPI) (age, sex, race) with “Black” estimate reported as “high value,” and “White” reported as “low value”a |
| (4) eGFRcr (CKD-EPI) (age, sex, race) with the Black coefficient ignored and eGFR value for White/other reported for all | (16) eGFRcr-cys (CKD-EPI) (age, sex, race) with the Black coefficient ignored and eGFR value for White/Other reported for all |
| (5) eGFRcr (CKD-EPI) (age, sex, race), with the Black coefficient used and eGFR value for African Americans reported for all | (17) eGFRcr-cys (CKD-EPI) (age, sex, race), with the Black coefficient used and eGFR value for African Americans reported for all |
| (6) Blended eGFRcr (CKD-EPI) (age, sex, race) using a single coefficient weighted for percentage of African Americans in the specific population reported for all | (18) Blended eGFRcr-cys (CKD-EPI) (age, sex, race) using a single coefficient weighted for percentage of African Americans in the specific population reported for all |
| Estimation with creatinine that do not include race | Estimation with cystatin C only |
| (7) CG estimated creatinine clearance (age, sex, weight)6,a,b | (19) eGFRcys (CKD-EPI) (age, sex)76,a |
| (8) eGFRcr (FAS) (age, sex)91 | (20) eGFRcys (FAS) (age, sex)92 |
| (9) eGFRcr (EKFC) (age, sex)93 | (21) eGFRcys (CAPA) (age)94 |
| (10) eGFR (LM) (age, sex)95 | |
| Equations to be developed to estimate GFR with creatinine that do not include race | Equations to be developed to estimate GFR with creatinine and cystatin C that do not include race |
| (11) eGFRcr refit without race variable | (22) eGFRcr-cys refit without race variable |
| (12) eGFRcr refit with height and weight without race variable | |
| Estimation with creatinine and cystatin C that does not include race | |
| (23) eGFRcr-cys (FAS) (age, sex)92 | |
| Estimations with new filtration markers in combination with creatinine or cystatin C that do not include race | |
| (24) eGFRcys-B2M-BTP (age, sex)96 | |
| (25) eGFRcr-cys-B2M-BTP (age, sex)96 | |
| (26) Any of the above either in combination or in sequence with measured GFR using exogenous filtration markers or measured creatinine clearance, to be used generally or by clinical indication (eg, donation, diagnosis, prescription, referral, transplant): Example: One of the above approaches followed by another approach for confirmation. | |
Parentheses indicate coefficients included in the development of the equation.
Abbreviations: B2M, β2-microglobulin; BTP, β-trace protein; CAPA, Caucasian and Asian Pediatric and Adult; CG, Cockcroft-Gault; CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; eGFRcr, estimated GFR from creatinine; eGFRcr-cys, estimated GFR from creatinine and cystatin C; eGFRcys, estimated GFR from cystatin C; EKFC, European Kidney Function Consortium; FAS, full age spectrum; LM, Lund-Malmo; MDRD, Modification of Diet in Renal Disease (Study).
a
Used or in use in at least one US setting.
b
CG creatinine clearance is reported in mL/min, eGFR results are standardized (or indexed) to a body surface area of 1.73 m2 and are reported in mL/min/1.73 m2.