Table 5.
Linear regression summary statistics of specimen comparisonsa
| Slope (95 % CI)b | Y-intercept (95 % CI)b (mg/L) | Correlation coefficient | 95 % CI at lower MDLc (mg/L) | 95 % CI at upper MDLc (mg/L) | |
|---|---|---|---|---|---|
| EDTA vs. serum | |||||
| Kappa | 0.969 (0.950–0.988) | 2.58 (1.54–3.64) | 0.9954 | 4.8–6.8 | 20.4–22.4 |
| Lambda | 0.995 (0.986–1.003) | 0.367 (0.127–0.608) | 0.9992 | 5.8–6.3 | 26.3–26.7 |
| κ/λ ratio | 1.001 (0.982–1.021) | 0.133 (0.066–0.199) | 0.9957 | 0.33–0.46 | 1.73–1.84 |
| Li-heparin plasma separator tube vs. serum | |||||
| Kappa | 1.081 (1.063–1.100) | 0.64 (−0.38 to 1.67) | 0.9964 | 3.2–5.2 | 19.4–22.5 |
| Lambda | 0.988 (0.981–1.000) | 0.279 (−0.101 to 0.557) | 1.0000 | 5.7–6.3 | 26.1–26.6 |
| κ/λ ratio | 1.175 (1.154–1.196) | −0.091 (−0.188 to 0.007) | 0.9961 | 0.12–0.31 | 1.65–1.83 |
aAnalysis uses Deming regression excluding outliers (see Table 4)
b CI confidence interval
c MDL medical decision limit: kappa, 3.3 and 19.4 mg/L; lambda, 5.7 and 26.3 mg/L; κ/λ ratio, 0.26 and 1.65