Table 1 Comprehensive method comparison analysis across study cohorts.
Analysis parameter | Without diabetes | With diabetes | Total cohort |
|---|---|---|---|
Sample size | 453 | 136 | 589 |
Bland-Altman analysis | |||
Mean bias, mg/dL (95% CI) | -3.80 (-5.39 to -2.20) | -1.64 (-5.90 to 2.60) | -3.30 (-4.87 to -1.74) |
Limits of agreement, mg/dL | -35.57 to 27.97 | -47.15 to 43.85 | -38.66 to 32.04 |
Proportional bias (Slope, p-value) | -0.08 (p=0.056) | 0.028 (p=0.464) | 0.01 (p=0.60) |
Coefficient of repeatability (95% CI) | 32.59 (30.48 to 35.03) | 45.42 (40.27 to 52.09) | 35.91 (33.85 to 38.25) |
Correlation | |||
Kendall’s Tau (95% CI) | 0.332 (0.261 to 0.396) | 0.668 (0.570 to 0.736) | 0.510 (0.435 to 0.541) |
Passing-Bablok regression | |||
Regression equation | POCT = 39.28 + 0.56 × Lab | POCT = 0.17 + 0.98 × Lab | POCT = 18.73 + 0.79 × Lab |
Intercept, A (95% CI) | 39.28 (32.31 to 45.25) | 0.17 (-12.08 to 12.54) | 18.73 (12.70 to 24.64) |
Slope, B (95% CI) | 0.56 (0.50 to 0.63) | 0.98 (0.89 to 1.07) | 0.79 (0.73 to 0.85) |
Residual standard deviation | 12.64 | 16.52 | 14.29 |
Cusum test (Linearity) | P = 0.01 | P = 0.47 | P < 0.01 |
Concordance analysis | |||
CCC (95% CI) | 0.679 (0.624 to 0.728) | 0.916 (0.882 to 0.941) | 0.886 (0.866 to 0.903) |
Precision (Pearson’s ρ) | 0.693 | 0.917 | 0.890 |
Accuracy (Cb) | 0.980 | 0.999 | 0.996 |
