Table 2.

Passing–Bablok regression and Spearman-rank correlation coefficients for agreement between GC-NICI-MS and ELISA measurements of urinary F₂-isoprostanes in 50 sick and healthy cats.

Comparison	Fixed bias/intercept*	Proportional bias/slope†	Correlation coefficient
GC-NICI-MS versus ELISA
All cats	0.09 (–0.04 to 0.2)	0.12 (0.05–0.18)	0.36 ( p = 0.009)
Healthy cats	0.22 (–0.04 to 0.46)	0.09 (0.02–0.18)	0.37 ( p = 0.07)
Systemically ill cats	0.1 (–0.07 to 0.2)	0.06 (0–0.23)	0.23 ( p = 0.27)

GC-NICI-MS = gas chromatography and negative ion chemical ionization–mass spectrometry.

^*Fixed bias was not identified in any comparison, as the 95% CI (in parentheses) for all intercepts includes 0.

^†Proportional bias was present in all comparisons given that the 95% CI (in parentheses) for all slopes did not include 1. Values of p ≤ 0.05 are considered significant.