Mean bias of eGFR in the accuracy-based creatinine proficiency testing program (2023)
| Sample name | eGFR equation | No. of participants without outlier |
Target value of eGFR (mL/min/1.73 m2) | Bias of eGFR | |
|---|---|---|---|---|---|
| Mean±SD (mL/min/1.73 m2) | Mean±SD (%) | ||||
| CAC-23-01 | CKD-EPI (2009) | 105 | 95.1 | −0.9±4.7 | −1.0±4.9 |
| CKD-EPI (2021) | 59 | 98.4 | −4.1±9.1 | −4.1±9.2 | |
| MDRD 4 variable (IDMS-traceable) | 420 | 81.8 | −0.4±6.5 | −0.5±8.0 | |
| MDRD 4 variable (non-IDMS-traceable) | 25 | 86.9 | −6.8±7.6 | −7.8±8.7 | |
| Cockcroft-Gault | 2 | 75.7 | −2.2±0.7 | −2.9±0.9 | |
| CAC-23-02 | CKD-EPI (2009) | 113 | 61.9 | −0.3±2.7 | −0.5±4.3 |
| CKD-EPI (2021) | 58 | 65.1 | −0.8±4.6 | −1.3±7.1 | |
| MDRD 4 variable (IDMS-traceable) | 437 | 56.9 | 0.6±3.5 | 1.0±6.1 | |
| MDRD 4 variable (non-IDMS-traceable) | 27 | 60.5 | −1.3±4.1 | −2.1±6.8 | |
| Cockcroft-Gault | 2 | 65.8 | 3.2±2.8 | 4.9±4.3 | |
| CAC-23-03 | CKD-EPI (2009) | 105 | 30.3 | 0.1±0.9 | 0.5±2.8 |
| CKD-EPI (2021) | 58 | 32.1 | −0.2±1.9 | −0.7±5.8 | |
| MDRD 4 variable (IDMS-traceable) | 434 | 28.9 | 0.6±1.6 | 2.0±5.5 | |
| MDRD 4 variable (non-IDMS-traceable) | 26 | 30.7 | −0.2±1.9 | −0.7±6.1 | |
| Cockcroft-Gault | 2 | 29.0 | 0.5±0.7 | 1.7±2.4 | |
| CAC-23-04 | CKD-EPI (2009) | 106 | 85.1 | −1.0±3.3 | −1.2±3.9 |
| CKD-EPI (2021) | 81 | 90.7 | −2.9±5.9 | −3.2±6.6 | |
| MDRD 4 variable (IDMS-traceable) | 444 | 82.4 | −0.8±6.1 | −1.0±7.4 | |
| MDRD 4 variable (non-IDMS-traceable) | 26 | 87.5 | −6.7±7.1 | −7.7±8.1 | |
| Cockcroft-Gault | 3 | 72.6 | −1.9±7.8 | −2.7±10.7 | |
| CAC-23-05 | CKD-EPI (2009) | 108 | 42.6 | 0.2±1.8 | 0.5±4.2 |
| CKD-EPI (2021) | 81 | 45.0 | −0.3±3.1 | −0.6±6.8 | |
| MDRD 4 variable (IDMS-traceable) | 425 | 40.0 | 0.4±2.3 | 0.9±5.9 | |
| MDRD 4 variable (non-IDMS-traceable) | 25 | 42.5 | −0.8±2.8 | −1.8±6.6 | |
| Cockcroft-Gault | 3 | 35.0 | 0.7±3.5 | 1.9±10.0 | |
| CAC-23-06 | CKD-EPI (2009) | 108 | 29.9 | −0.2±1.0 | −0.6±3.5 |
| CKD-EPI (2021) | 81 | 31.6 | −0.2±2.1 | −0.5±6.7 | |
| MDRD 4 variable (IDMS-traceable) | 426 | 28.1 | 0.2±1.6 | 0.6±5.5 | |
| MDRD 4 variable (non-IDMS-traceable) | 25 | 29.9 | 0±1.9 | −0.1±6.3 | |
| Cockcroft-Gault | 3 | 32.4 | 0.3±3.1 | 0.8±9.4 | |
Abbreviations: eGFR, estimated glomerular filtration rate; SD, standard deviation; CKD-EPI, Chronic Kidney Disease Epidemiology Collaboration; MDRD, Modification of Diet in Renal Disease; IDMS, isotope dilution mass spectrometry; IQR, interquartile range; Q1, 25th percentile; Q3, 75th percentile.
*The outliers were defined as less than Q1−1.5×IQR or greater than Q3+1.5×IQR and were excluded from the analysis.