Table 1.
Characteristics of the Subjects.
Table 2.
Comparison mGFR 99Tcm DTPA to bedside Schwartz and EKFC.
Fig 1.
Passing–Bablok regression and Bland–Altman analysis comparing EKFC eGFR with measured GFR (Tc-99m DTPA) in the full cohort (n = 276). (A) The Passing–Bablok regression shows the relationship between EKFC-estimated GFR and mGFR99mTc-DTPA. The regression equation (y = –11.174 + 0.957x) demonstrates a slope slightly below unity, indicating mild proportional underestimation by the EKFC equation at higher GFR values. The 95% confidence interval band (shaded blue) reflects narrow dispersion, particularly between GFR 50–200 mL/min/1.73 m², where most data points cluster. The identity line (x = y) is shown in red for reference. (B) The Bland–Altman plot displays the bias (mean difference: –20.8 mL/min/1.73 m²) and limits of agreement (–52.6 to +11.1 mL/min/1.73 m²). Most points fall within limits, but a consistent negative bias indicates systematic underestimation of GFR by EKFC relative to mGFR. One high-GFR outlier (>400 mL/min/1.73 m²) is visible.
Fig 2.
Passing–Bablok regression and Bland–Altman analysis comparing bedside Schwartz eGFR with measured GFR (Tc-99m DTPA) in the full cohort (n = 276). (A) The Passing–Bablok regression (y = 37.286 + 0.810x) indicates substantial constant bias (intercept ≈ 37 mL/min/1.73 m²) and a slope <1.0, showing that the bedside Schwartz equation progressively underestimates mGFR at higher values. The wide blue-shaded confidence band highlights increased variability at higher GFRs. (B) The Bland–Altman plot shows mean positive bias (+19.9 mL/min/1.73 m²), indicating that bedside Schwartz overestimates GFR overall in this population. Limits of agreement range from –26.7 to +66.6 mL/min/1.73 m². Several scattered residuals at low GFR values indicate broad dispersion and lower precision.
Fig 3.
Passing–Bablok regression and Bland–Altman analysis comparing CKiD-U25 creatinine eGFR with measured GFR (Tc-99m DTPA) in the full cohort (n = 276) (A) Passing-bablok regression analysis (y = 37.246 + 0.806x) shows constant and proportional bias. The slope <1.0 suggests GFR underestimation at higher ranges. The confidence band widens moderately toward high GFR values (>200 mL/min/1.73 m²), reflecting greater uncertainty. (B) Bland–Altman analysis indicates mean bias of +19.7 mL/min/1.73 m², with LOA between –27.0 and +66.4 mL/min/1.73 m².
Fig 4.
Passing–Bablok regression and Bland–Altman analysis comparing EKFC eGFR with measured GFR (Tc-99m DTPA) in children aged >2 years (n = 229). (A) Passing-Bablok regression (y = –12.549 + 0.973x) demonstrates strong agreement, with slope near 1.0 and narrow confidence intervals. Compared with the full cohort, dispersion around the identity line is reduced, suggesting improved performance of EKFC in children >2 years. (B) Bland–Altman analysis reveals mean bias of –17.7 mL/min/1.73 m² with LOA from –42.7 to +7.4 mL/min/1.73 m². Variability is notably lower than in the full cohort, indicating the EKFC equation is more accurate and precise when applied to children older than 2 years.
Fig 5.
Passing–Bablok regression and Bland–Altman analysis comparing bedside Schwartz eGFR with measured GFR (Tc-99m DTPA) in children aged >2 years (n = 229). (A) The Passing-Bablok regression equation (y = 37.095 + 0.810x) maintains a similar bias structure as in the full cohort, but with reduced scatter. The shaded confidence band remains wider than EKFC, illustrating lower precision in this age group. (B) Bland–Altman results show mean bias of +18.5 mL/min/1.73 m² and LOA from –26.3 to +63.3 mL/min/1.73 m². The persistent positive bias indicates overestimation of GFR by bedside Schwartz, particularly between 80–150 mL/min/1.73 m² where most data points lie.
Fig 6.
Passing–Bablok regression and Bland–Altman analysis comparing CKiD-U25 eGFR with measured GFR (Tc-99m DTPA) in children aged >2 years (n = 229). (A) Passing-Bablok regression (y = 37.063 + 0.806x) shows nearly identical behavior to bedside Schwartz, with similar intercept and slope. Prediction intervals widen at high GFR values, indicating less stability beyond 150–200 mL/min/1.73 m². (B) Bland–Altman analysis indicates mean bias of +18.3 mL/min/1.73 m² and LOA from –26.6 to +63.2 mL/min/1.73 m².
Table 3.
Classification of kidney function comparison mGFR to EKFC, bedside Schwartz and CKiD-U25.