Table 1.

Passing–Bablok regression analysis comparing ‘traditional’ and ‘one-sample’ approaches to measure red blood cell glutathione FSR

Regression analysis 1
Variable X	Variable Y
Absolute glutathione FSR values (traditional equation)	Absolute glutathione FSR values (one-sample equation)
	Value	95%c.i.
Intercept A	−0.02	from −11.32 to 7.01
Slope B	0.86	from 0.68 to 1.04
Cusum test for linearity	No significant deviation from linearity (P > 0.05)
Regression analysis 2
Variable X	Variable Y
Glutathione FSR changes (traditional equation)	Glutathione FSR changes (One-sample equation)
	Value	95%c.i.
Intercept A	0.95	from −9.10 to 1.47
Slope B	0.91	from 0.75 to 1.20
Cusum test for linearity	No significant deviation from linearity (P > 0.05)

Table shows results of two separate regression line analyses performed by the Passing–Bablok method (see Fig. 5). Regression analysis 1 was performed to compare absolute glutathione fractional synthesis rate (FSR) values measured by ‘traditional’ approach (X variable) with the same values measured by the ‘one-sample’ (Y variable) approach. Regression analysis 2 was performed to compare changes from baseline to day 7 and to day 33 of glutathione FSR measured by the traditional equation (Variable X), with the same values measured by one-sample equation (Variable Y). Both analyses show inclusion in the relative confidence interval (95%c.i.) of each Intercept A and Slope B value characterizing obtained regression lines. Additionally, in both analyses linear distribution was confirmed by an appropriate test.